diff --git a/audio/core/all-versions/vts/functional/4.0/AudioPrimaryHidlHalTest.cpp b/audio/core/all-versions/vts/functional/4.0/AudioPrimaryHidlHalTest.cpp
index 1612d3c..9a4a8b2 100644
--- a/audio/core/all-versions/vts/functional/4.0/AudioPrimaryHidlHalTest.cpp
+++ b/audio/core/all-versions/vts/functional/4.0/AudioPrimaryHidlHalTest.cpp
@@ -140,20 +140,23 @@
 #if MAJOR_VERSION <= 6
     using AD = AudioDevice;
     for (auto deviceType : {AD::OUT_HDMI, AD::OUT_WIRED_HEADPHONE, AD::IN_USB_HEADSET}) {
+        SCOPED_TRACE("device=" + ::testing::PrintToString(deviceType));
 #elif MAJOR_VERSION >= 7
     using AD = xsd::AudioDevice;
-    for (auto deviceType :
-         {toString(AD::AUDIO_DEVICE_OUT_HDMI), toString(AD::AUDIO_DEVICE_OUT_WIRED_HEADPHONE),
-          toString(AD::AUDIO_DEVICE_IN_USB_HEADSET)}) {
+    for (auto deviceType : {AD::AUDIO_DEVICE_OUT_HDMI, AD::AUDIO_DEVICE_OUT_WIRED_HEADPHONE,
+                            AD::AUDIO_DEVICE_IN_USB_HEADSET}) {
+        SCOPED_TRACE("device=" + toString(deviceType));
 #endif
-        SCOPED_TRACE("device=" + ::testing::PrintToString(deviceType));
         for (bool state : {true, false}) {
             SCOPED_TRACE("state=" + ::testing::PrintToString(state));
             DeviceAddress address = {};
 #if MAJOR_VERSION <= 6
             address.device = deviceType;
 #elif MAJOR_VERSION >= 7
-            address.deviceType = deviceType;
+            address.deviceType = toString(deviceType);
+            if (deviceType == AD::AUDIO_DEVICE_IN_USB_HEADSET) {
+                address.address.alsa({0, 0});
+            }
 #endif
             auto ret = getDevice()->setConnectedState(address, state);
             ASSERT_TRUE(ret.isOk());
diff --git a/audio/core/all-versions/vts/functional/7.0/AudioPrimaryHidlHalTest.cpp b/audio/core/all-versions/vts/functional/7.0/AudioPrimaryHidlHalTest.cpp
index 941c4bd..6bb7995 100644
--- a/audio/core/all-versions/vts/functional/7.0/AudioPrimaryHidlHalTest.cpp
+++ b/audio/core/all-versions/vts/functional/7.0/AudioPrimaryHidlHalTest.cpp
@@ -44,22 +44,26 @@
         for (const auto& device : getDeviceParameters()) {
             auto module =
                     getCachedPolicyConfig().getModuleFromName(std::get<PARAM_DEVICE_NAME>(device));
+            if (!module || !module->getFirstMixPorts()) break;
             for (const auto& mixPort : module->getFirstMixPorts()->getMixPort()) {
                 if (mixPort.getRole() != xsd::Role::source) continue;  // not an output profile
-                auto xsdFlags = mixPort.getFlags();
-                const bool isOffload =
-                        std::find(xsdFlags.begin(), xsdFlags.end(),
-                                  xsd::AudioInOutFlag::AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD) !=
-                        xsdFlags.end();
                 std::vector<AudioInOutFlag> flags;
-                if (!isOffload) {
-                    for (auto flag : xsdFlags) {
-                        if (flag != xsd::AudioInOutFlag::AUDIO_OUTPUT_FLAG_PRIMARY) {
-                            flags.push_back(toString(flag));
+                bool isOffload = false;
+                if (mixPort.hasFlags()) {
+                    auto xsdFlags = mixPort.getFlags();
+                    isOffload =
+                            std::find(xsdFlags.begin(), xsdFlags.end(),
+                                      xsd::AudioInOutFlag::AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD) !=
+                            xsdFlags.end();
+                    if (!isOffload) {
+                        for (auto flag : xsdFlags) {
+                            if (flag != xsd::AudioInOutFlag::AUDIO_OUTPUT_FLAG_PRIMARY) {
+                                flags.push_back(toString(flag));
+                            }
                         }
+                    } else {
+                        flags = offloadFlags;
                     }
-                } else {
-                    flags = offloadFlags;
                 }
                 for (const auto& profile : mixPort.getProfile()) {
                     auto configs =
@@ -94,11 +98,15 @@
         for (const auto& device : getDeviceParameters()) {
             auto module =
                     getCachedPolicyConfig().getModuleFromName(std::get<PARAM_DEVICE_NAME>(device));
+            if (!module || !module->getFirstMixPorts()) break;
             for (const auto& mixPort : module->getFirstMixPorts()->getMixPort()) {
                 if (mixPort.getRole() != xsd::Role::sink) continue;  // not an input profile
                 std::vector<AudioInOutFlag> flags;
-                std::transform(mixPort.getFlags().begin(), mixPort.getFlags().end(), flags.begin(),
-                               [](auto flag) { return toString(flag); });
+                if (mixPort.hasFlags()) {
+                    std::transform(mixPort.getFlags().begin(), mixPort.getFlags().end(),
+                                   std::back_inserter(flags),
+                                   [](auto flag) { return toString(flag); });
+                }
                 for (const auto& profile : mixPort.getProfile()) {
                     auto configs =
                             combineAudioConfig(profile.getChannelMasks(),
diff --git a/audio/core/all-versions/vts/functional/7.0/PolicyConfig.h b/audio/core/all-versions/vts/functional/7.0/PolicyConfig.h
index d790b34..7d88642 100644
--- a/audio/core/all-versions/vts/functional/7.0/PolicyConfig.h
+++ b/audio/core/all-versions/vts/functional/7.0/PolicyConfig.h
@@ -33,10 +33,14 @@
         if (mConfig) {
             mStatus = OK;
             mPrimaryModule = getModuleFromName(DeviceManager::kPrimaryDevice);
-            for (const auto& module : mConfig->getFirstModules()->get_module()) {
-                auto attachedDevices = module.getFirstAttachedDevices()->getItem();
-                if (!attachedDevices.empty()) {
-                    mModulesWithDevicesNames.insert(module.getName());
+            if (mConfig->getFirstModules()) {
+                for (const auto& module : mConfig->getFirstModules()->get_module()) {
+                    if (module.getFirstAttachedDevices()) {
+                        auto attachedDevices = module.getFirstAttachedDevices()->getItem();
+                        if (!attachedDevices.empty()) {
+                            mModulesWithDevicesNames.insert(module.getName());
+                        }
+                    }
                 }
             }
         }
@@ -52,7 +56,7 @@
     }
     const std::string& getFilePath() const { return mFilePath; }
     const xsd::Module* getModuleFromName(const std::string& name) const {
-        if (mConfig) {
+        if (mConfig && mConfig->getFirstModules()) {
             for (const auto& module : mConfig->getFirstModules()->get_module()) {
                 if (module.getName() == name) return &module;
             }
@@ -65,8 +69,10 @@
     }
     bool haveInputProfilesInModule(const std::string& name) const {
         auto module = getModuleFromName(name);
-        for (const auto& mixPort : module->getFirstMixPorts()->getMixPort()) {
-            if (mixPort.getRole() == xsd::Role::sink) return true;
+        if (module && module->getFirstMixPorts()) {
+            for (const auto& mixPort : module->getFirstMixPorts()->getMixPort()) {
+                if (mixPort.getRole() == xsd::Role::sink) return true;
+            }
         }
         return false;
     }
diff --git a/audio/core/all-versions/vts/functional/AudioPrimaryHidlHalTest.h b/audio/core/all-versions/vts/functional/AudioPrimaryHidlHalTest.h
index 05c9bf7..43c44cb 100644
--- a/audio/core/all-versions/vts/functional/AudioPrimaryHidlHalTest.h
+++ b/audio/core/all-versions/vts/functional/AudioPrimaryHidlHalTest.h
@@ -156,6 +156,21 @@
     return *policyConfig;
 }
 
+TEST(CheckConfig, audioPolicyConfigurationValidation) {
+    const auto factories = ::android::hardware::getAllHalInstanceNames(IDevicesFactory::descriptor);
+    if (factories.size() == 0) {
+        GTEST_SKIP() << "Skipping audioPolicyConfigurationValidation because no factory instances "
+                        "are found.";
+    }
+    RecordProperty("description",
+                   "Verify that the audio policy configuration file "
+                   "is valid according to the schema");
+
+    const char* xsd = "/data/local/tmp/audio_policy_configuration_" STRINGIFY(CPP_VERSION) ".xsd";
+    EXPECT_ONE_VALID_XML_MULTIPLE_LOCATIONS(kConfigFileName,
+                                            android::audio_get_configuration_paths(), xsd);
+}
+
 //////////////////////////////////////////////////////////////////////////////
 //////////////////// Test parameter types and definitions ////////////////////
 //////////////////////////////////////////////////////////////////////////////
@@ -231,21 +246,6 @@
     }
 };
 
-TEST(CheckConfig, audioPolicyConfigurationValidation) {
-    auto deviceParameters = getDeviceParametersForFactoryTests();
-    if (deviceParameters.size() == 0) {
-        GTEST_SKIP() << "Skipping audioPolicyConfigurationValidation because no device parameter "
-                        "is found.";
-    }
-    RecordProperty("description",
-                   "Verify that the audio policy configuration file "
-                   "is valid according to the schema");
-
-    const char* xsd = "/data/local/tmp/audio_policy_configuration_" STRINGIFY(CPP_VERSION) ".xsd";
-    EXPECT_ONE_VALID_XML_MULTIPLE_LOCATIONS(kConfigFileName,
-                                            android::audio_get_configuration_paths(), xsd);
-}
-
 class AudioPolicyConfigTest : public AudioHidlTestWithDeviceParameter {
   public:
     void SetUp() override {
diff --git a/automotive/can/1.0/default/libnl++/Android.bp b/automotive/can/1.0/default/libnl++/Android.bp
index 90e1002..a69e302 100644
--- a/automotive/can/1.0/default/libnl++/Android.bp
+++ b/automotive/can/1.0/default/libnl++/Android.bp
@@ -22,6 +22,7 @@
         "protocols/common/Empty.cpp",
         "protocols/common/Error.cpp",
         "protocols/generic/Ctrl.cpp",
+        "protocols/generic/FamilyTracker.cpp",
         "protocols/generic/Generic.cpp",
         "protocols/generic/GenericMessageBase.cpp",
         "protocols/generic/Unknown.cpp",
@@ -34,6 +35,7 @@
         "protocols/all.cpp",
         "Attributes.cpp",
         "MessageFactory.cpp",
+        "MessageMutator.cpp",
         "Socket.cpp",
         "common.cpp",
         "printer.cpp",
diff --git a/automotive/can/1.0/default/libnl++/MessageMutator.cpp b/automotive/can/1.0/default/libnl++/MessageMutator.cpp
new file mode 100644
index 0000000..00b48a6
--- /dev/null
+++ b/automotive/can/1.0/default/libnl++/MessageMutator.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <libnl++/MessageMutator.h>
+
+namespace android::nl {
+
+MessageMutator::MessageMutator(nlmsghdr* buffer, size_t totalLen)
+    : mConstBuffer(buffer, totalLen), mMutableBuffer(buffer) {
+    CHECK(totalLen >= sizeof(nlmsghdr));
+}
+
+nlmsghdr* MessageMutator::operator->() const {
+    return mMutableBuffer;
+}
+
+MessageMutator::operator Buffer<nlmsghdr>() const {
+    return mConstBuffer;
+}
+
+uint64_t MessageMutator::read(Buffer<nlattr> attr) const {
+    return attr.data<uint64_t>().copyFirst();
+}
+
+void MessageMutator::write(Buffer<nlattr> attr, uint64_t val) const {
+    const auto attrData = attr.data<uint64_t>();
+    const auto offset = mConstBuffer.getOffset(attrData);
+    CHECK(offset.has_value()) << "Trying to write attribute that's not a member of this message";
+
+    const auto writeableBuffer = reinterpret_cast<uint8_t*>(mMutableBuffer) + *offset;
+    const auto attrSize = attrData.getRaw().len();
+
+    if (attrSize > sizeof(val)) memset(writeableBuffer, 0, attrSize);
+    memcpy(writeableBuffer, &val, std::min(sizeof(val), attrSize));
+}
+
+}  // namespace android::nl
diff --git a/automotive/can/1.0/default/libnl++/include/libnl++/Attributes.h b/automotive/can/1.0/default/libnl++/include/libnl++/Attributes.h
index f16d997..a438a69 100644
--- a/automotive/can/1.0/default/libnl++/include/libnl++/Attributes.h
+++ b/automotive/can/1.0/default/libnl++/include/libnl++/Attributes.h
@@ -93,14 +93,29 @@
      */
     template <typename T>
     T get(nlattrtype_t attrtype) const {
-        const auto& ind = index();
-        const auto it = ind.find(attrtype);
-        if (it == ind.end()) {
+        const auto buffer = getBuffer(attrtype);
+        if (!buffer.has_value()) {
             LOG(WARNING) << "Netlink attribute is missing: " << attrtype;
             return T{};
         }
 
-        return parse<T>(it->second);
+        return parse<T>(*buffer);
+    }
+
+    /**
+     * Fetches underlying buffer of a given attribute.
+     *
+     * This is a low-level access method unlikely to be useful in most cases. Please consider
+     * using #get instead.
+     *
+     * \param attrtype Attribute to fetch
+     * \return Attribute buffer.
+     */
+    std::optional<Buffer<nlattr>> getBuffer(nlattrtype_t attrtype) const {
+        const auto& ind = index();
+        const auto it = ind.find(attrtype);
+        if (it == ind.end()) return std::nullopt;
+        return it->second;
     }
 
     /**
diff --git a/automotive/can/1.0/default/libnl++/include/libnl++/Buffer.h b/automotive/can/1.0/default/libnl++/include/libnl++/Buffer.h
index bf83fbc..d759a0a 100644
--- a/automotive/can/1.0/default/libnl++/include/libnl++/Buffer.h
+++ b/automotive/can/1.0/default/libnl++/include/libnl++/Buffer.h
@@ -91,6 +91,18 @@
         return {impl::data<const T, const D>(mData, offset), dataEnd()};
     }
 
+    template <typename B>
+    std::optional<uintptr_t> getOffset(Buffer<B> inner) const {
+        const auto selfStart = uintptr_t(mData);
+        const auto selfEnd = uintptr_t(mBufferEnd);
+        const auto innerStart = uintptr_t(inner.mData);
+        const auto innerEnd = uintptr_t(inner.mBufferEnd);
+
+        if (innerStart < selfStart || innerEnd > selfEnd) return std::nullopt;
+
+        return innerStart - selfStart;
+    }
+
     class iterator {
       public:
         iterator() : mCurrent(nullptr, size_t(0)) {
diff --git a/automotive/can/1.0/default/libnl++/include/libnl++/MessageMutator.h b/automotive/can/1.0/default/libnl++/include/libnl++/MessageMutator.h
new file mode 100644
index 0000000..7d495e9
--- /dev/null
+++ b/automotive/can/1.0/default/libnl++/include/libnl++/MessageMutator.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <libnl++/Message.h>
+
+namespace android::nl {
+
+/**
+ * In-place message mutator.
+ *
+ * Useful for making small changes (such as adjusting const-sized attributes or struct fields)
+ * efficiently and in-place. However, if you need to rebuild the message (e.g. to modify variable
+ * sized attributes or add/remove them), you need to use MessageFactory instead.
+ */
+class MessageMutator {
+  public:
+    /**
+     * Construct message mutator object from editable buffer.
+     */
+    MessageMutator(nlmsghdr* buffer, size_t totalLen);
+
+    nlmsghdr* operator->() const;
+    operator Buffer<nlmsghdr>() const;
+
+    /**
+     * Read current attribute value.
+     *
+     * \param Read-only attribute buffer.
+     * \returns Attribute value.
+     */
+    uint64_t read(Buffer<nlattr> attr) const;
+
+    /**
+     * Write new attribute value.
+     *
+     * \param Read-only attribute buffer.
+     * \param val New value to set.
+     */
+    void write(Buffer<nlattr> attr, uint64_t val) const;
+
+  private:
+    const Buffer<nlmsghdr> mConstBuffer;
+    nlmsghdr* mMutableBuffer;
+};
+
+}  // namespace android::nl
diff --git a/automotive/can/1.0/default/libnl++/include/libnl++/generic/FamilyTracker.h b/automotive/can/1.0/default/libnl++/include/libnl++/generic/FamilyTracker.h
new file mode 100644
index 0000000..2530035
--- /dev/null
+++ b/automotive/can/1.0/default/libnl++/include/libnl++/generic/FamilyTracker.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <libnl++/Buffer.h>
+#include <libnl++/Message.h>
+
+#include <linux/genetlink.h>
+
+#include <optional>
+
+namespace android::nl::generic {
+
+/**
+ * Tracker of Netlink family ID registrations.
+ */
+class FamilyTracker {
+  public:
+    /**
+     * Try parsing NL80211 message.
+     *
+     * Proper parsing of NL80211 nessages requires prior parsing of control message for Generic
+     * Netlink protocol.
+     *
+     * \param msg Message to parse
+     * \returns Parsed NL80211 message or std::nullopt if it wasn't one
+     */
+    std::optional<Message<genlmsghdr>> parseNl80211(Buffer<nlmsghdr> msg);
+
+  private:
+    /* For efficiency, we use a single hardcoded family ID. However, if we supported multiple family
+     * types, this should probably be a map.
+     */
+    std::optional<uint16_t> mNl80211FamilyId;
+
+    /**
+     * Track Generic protocol messages.
+     *
+     * This method is looking for family registration messages.
+     *
+     * \param msg Message to track
+     * \returns True, if the message was a control message (regardless of carrying
+     *          family info or not)
+     */
+    bool track(const Buffer<nlmsghdr>& msg);
+};
+
+}  // namespace android::nl::generic
diff --git a/automotive/can/1.0/default/libnl++/protocols/generic/FamilyTracker.cpp b/automotive/can/1.0/default/libnl++/protocols/generic/FamilyTracker.cpp
new file mode 100644
index 0000000..900560e
--- /dev/null
+++ b/automotive/can/1.0/default/libnl++/protocols/generic/FamilyTracker.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <libnl++/generic/FamilyTracker.h>
+
+#include <android-base/logging.h>
+
+namespace android::nl::generic {
+
+bool FamilyTracker::track(const Buffer<nlmsghdr>& buffer) {
+    const auto msgMaybe = nl::Message<genlmsghdr>::parse(buffer, {GENL_ID_CTRL});
+    if (!msgMaybe.has_value()) return false;
+
+    const auto msg = *msgMaybe;
+    if (msg->cmd != CTRL_CMD_NEWFAMILY) return true;
+
+    const auto familyName = msg.attributes.get<std::string>(CTRL_ATTR_FAMILY_NAME);
+    const auto familyId = msg.attributes.get<uint16_t>(CTRL_ATTR_FAMILY_ID);
+
+    if (familyId < GENL_START_ALLOC) {
+        LOG(WARNING) << "Invalid family ID: " << familyId;
+        return true;
+    }
+
+    if (familyName == "nl80211") mNl80211FamilyId = familyId;
+
+    return true;
+}
+
+std::optional<Message<genlmsghdr>> FamilyTracker::parseNl80211(Buffer<nlmsghdr> msg) {
+    if (track(msg)) return std::nullopt;
+    if (!mNl80211FamilyId.has_value()) return std::nullopt;
+
+    return nl::Message<genlmsghdr>::parse(msg, {*mNl80211FamilyId});
+}
+
+}  // namespace android::nl::generic
diff --git a/neuralnetworks/1.0/utils/include/nnapi/hal/1.0/Callbacks.h b/neuralnetworks/1.0/utils/include/nnapi/hal/1.0/Callbacks.h
index 2e00fce..3b32e1d 100644
--- a/neuralnetworks/1.0/utils/include/nnapi/hal/1.0/Callbacks.h
+++ b/neuralnetworks/1.0/utils/include/nnapi/hal/1.0/Callbacks.h
@@ -32,6 +32,26 @@
 
 namespace android::hardware::neuralnetworks::V1_0::utils {
 
+// Converts the results of IDevice::getSupportedOperations* to the NN canonical format. On success,
+// this function returns with the supported operations as indicated by a driver. On failure, this
+// function returns with the appropriate nn::GeneralError.
+nn::GeneralResult<std::vector<bool>> supportedOperationsCallback(
+        ErrorStatus status, const hidl_vec<bool>& supportedOperations);
+
+// Converts the results of IDevice::prepareModel* to the NN canonical format. On success, this
+// function returns with a non-null nn::SharedPreparedModel with a feature level of
+// nn::Version::ANDROID_OC_MR1. On failure, this function returns with the appropriate
+// nn::GeneralError.
+nn::GeneralResult<nn::SharedPreparedModel> prepareModelCallback(
+        ErrorStatus status, const sp<IPreparedModel>& preparedModel);
+
+// Converts the results of IDevice::execute* to the NN canonical format. On success, this function
+// returns with an empty output shape vector and no timing information. On failure, this function
+// returns with the appropriate nn::ExecutionError.
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executionCallback(
+        ErrorStatus status);
+
+// A HIDL callback class to receive the results of IDevice::prepareModel asynchronously.
 class PreparedModelCallback final : public IPreparedModelCallback,
                                     public hal::utils::IProtectedCallback {
   public:
@@ -44,11 +64,10 @@
     Data get();
 
   private:
-    void notifyInternal(Data result);
-
     hal::utils::TransferValue<Data> mData;
 };
 
+// A HIDL callback class to receive the results of IDevice::execute asynchronously.
 class ExecutionCallback final : public IExecutionCallback, public hal::utils::IProtectedCallback {
   public:
     using Data = nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>;
@@ -60,8 +79,6 @@
     Data get();
 
   private:
-    void notifyInternal(Data result);
-
     hal::utils::TransferValue<Data> mData;
 };
 
diff --git a/neuralnetworks/1.0/utils/src/Callbacks.cpp b/neuralnetworks/1.0/utils/src/Callbacks.cpp
index a0bdb3c..ea3ea56 100644
--- a/neuralnetworks/1.0/utils/src/Callbacks.cpp
+++ b/neuralnetworks/1.0/utils/src/Callbacks.cpp
@@ -27,6 +27,7 @@
 #include <nnapi/Result.h>
 #include <nnapi/Types.h>
 #include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/HandleError.h>
 #include <nnapi/hal/ProtectCallback.h>
 #include <nnapi/hal/TransferValue.h>
 
@@ -36,63 +37,52 @@
 // lifetimes across processes and for protecting asynchronous calls across HIDL.
 
 namespace android::hardware::neuralnetworks::V1_0::utils {
-namespace {
 
-nn::GeneralResult<nn::SharedPreparedModel> convertPreparedModel(
-        const sp<IPreparedModel>& preparedModel) {
-    return NN_TRY(utils::PreparedModel::create(preparedModel));
+nn::GeneralResult<std::vector<bool>> supportedOperationsCallback(
+        ErrorStatus status, const hidl_vec<bool>& supportedOperations) {
+    HANDLE_HAL_STATUS(status) << "get supported operations failed with " << toString(status);
+    return supportedOperations;
 }
 
-}  // namespace
+nn::GeneralResult<nn::SharedPreparedModel> prepareModelCallback(
+        ErrorStatus status, const sp<IPreparedModel>& preparedModel) {
+    HANDLE_HAL_STATUS(status) << "model preparation failed with " << toString(status);
+    return NN_TRY(PreparedModel::create(preparedModel));
+}
+
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executionCallback(
+        ErrorStatus status) {
+    HANDLE_HAL_STATUS(status) << "execution failed with " << toString(status);
+    return {};
+}
 
 Return<void> PreparedModelCallback::notify(ErrorStatus status,
                                            const sp<IPreparedModel>& preparedModel) {
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "preparedModel failed with " << toString(status));
-    } else if (preparedModel == nullptr) {
-        notifyInternal(NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                       << "Returned preparedModel is nullptr");
-    } else {
-        notifyInternal(convertPreparedModel(preparedModel));
-    }
+    mData.put(prepareModelCallback(status, preparedModel));
     return Void();
 }
 
 void PreparedModelCallback::notifyAsDeadObject() {
-    notifyInternal(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
+    mData.put(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
 }
 
 PreparedModelCallback::Data PreparedModelCallback::get() {
     return mData.take();
 }
 
-void PreparedModelCallback::notifyInternal(PreparedModelCallback::Data result) {
-    mData.put(std::move(result));
-}
-
 // ExecutionCallback methods begin here
 
 Return<void> ExecutionCallback::notify(ErrorStatus status) {
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "execute failed with " << toString(status));
-    } else {
-        notifyInternal({});
-    }
+    mData.put(executionCallback(status));
     return Void();
 }
 
 void ExecutionCallback::notifyAsDeadObject() {
-    notifyInternal(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
+    mData.put(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
 }
 
 ExecutionCallback::Data ExecutionCallback::get() {
     return mData.take();
 }
 
-void ExecutionCallback::notifyInternal(ExecutionCallback::Data result) {
-    mData.put(std::move(result));
-}
-
 }  // namespace android::hardware::neuralnetworks::V1_0::utils
diff --git a/neuralnetworks/1.0/utils/src/Device.cpp b/neuralnetworks/1.0/utils/src/Device.cpp
index 83e0015..93bd81a 100644
--- a/neuralnetworks/1.0/utils/src/Device.cpp
+++ b/neuralnetworks/1.0/utils/src/Device.cpp
@@ -31,6 +31,7 @@
 #include <nnapi/hal/CommonUtils.h>
 #include <nnapi/hal/HandleError.h>
 #include <nnapi/hal/ProtectCallback.h>
+#include <nnapi/hal/TransferValue.h>
 
 #include <functional>
 #include <memory>
@@ -44,24 +45,21 @@
 namespace android::hardware::neuralnetworks::V1_0::utils {
 namespace {
 
-nn::GeneralResult<nn::Capabilities> initCapabilities(V1_0::IDevice* device) {
+nn::GeneralResult<nn::Capabilities> capabilitiesCallback(ErrorStatus status,
+                                                         const Capabilities& capabilities) {
+    HANDLE_HAL_STATUS(status) << "getting capabilities failed with " << toString(status);
+    return nn::convert(capabilities);
+}
+
+nn::GeneralResult<nn::Capabilities> getCapabilitiesFrom(V1_0::IDevice* device) {
     CHECK(device != nullptr);
 
-    nn::GeneralResult<nn::Capabilities> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                 << "uninitialized";
-    const auto cb = [&result](ErrorStatus status, const Capabilities& capabilities) {
-        if (status != ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "getCapabilities failed with " << toString(status);
-        } else {
-            result = nn::convert(capabilities);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(capabilitiesCallback);
 
     const auto ret = device->getCapabilities(cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 }  // namespace
@@ -77,7 +75,7 @@
                << "V1_0::utils::Device::create must have non-null device";
     }
 
-    auto capabilities = NN_TRY(initCapabilities(device.get()));
+    auto capabilities = NN_TRY(getCapabilitiesFrom(device.get()));
 
     auto deathHandler = NN_TRY(hal::utils::DeathHandler::create(device));
     return std::make_shared<const Device>(PrivateConstructorTag{}, std::move(name),
@@ -134,27 +132,12 @@
 
     const auto hidlModel = NN_TRY(convert(modelInShared));
 
-    nn::GeneralResult<std::vector<bool>> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                  << "uninitialized";
-    auto cb = [&result, &model](ErrorStatus status, const hidl_vec<bool>& supportedOperations) {
-        if (status != ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical)
-                     << "getSupportedOperations failed with " << toString(status);
-        } else if (supportedOperations.size() != model.main.operations.size()) {
-            result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                     << "getSupportedOperations returned vector of size "
-                     << supportedOperations.size() << " but expected "
-                     << model.main.operations.size();
-        } else {
-            result = supportedOperations;
-        }
-    };
+    auto cb = hal::utils::CallbackValue(supportedOperationsCallback);
 
     const auto ret = kDevice->getSupportedOperations(hidlModel, cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 nn::GeneralResult<nn::SharedPreparedModel> Device::prepareModel(
@@ -173,10 +156,7 @@
 
     const auto ret = kDevice->prepareModel(hidlModel, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "prepareModel failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "model preparation failed with " << toString(status);
 
     return cb->get();
 }
diff --git a/neuralnetworks/1.0/utils/src/PreparedModel.cpp b/neuralnetworks/1.0/utils/src/PreparedModel.cpp
index c1dd1d9..c0c22fb 100644
--- a/neuralnetworks/1.0/utils/src/PreparedModel.cpp
+++ b/neuralnetworks/1.0/utils/src/PreparedModel.cpp
@@ -42,8 +42,7 @@
 nn::GeneralResult<std::shared_ptr<const PreparedModel>> PreparedModel::create(
         sp<V1_0::IPreparedModel> preparedModel) {
     if (preparedModel == nullptr) {
-        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
-               << "V1_0::utils::PreparedModel::create must have non-null preparedModel";
+        return NN_ERROR() << "V1_0::utils::PreparedModel::create must have non-null preparedModel";
     }
 
     auto deathHandler = NN_TRY(hal::utils::DeathHandler::create(preparedModel));
@@ -71,10 +70,7 @@
 
     const auto ret = kPreparedModel->execute(hidlRequest, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "execute failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "execution failed with " << toString(status);
 
     auto result = NN_TRY(cb->get());
     NN_TRY(hal::utils::makeExecutionFailure(
diff --git a/neuralnetworks/1.1/utils/include/nnapi/hal/1.1/Conversions.h b/neuralnetworks/1.1/utils/include/nnapi/hal/1.1/Conversions.h
index f646462..5d0769f 100644
--- a/neuralnetworks/1.1/utils/include/nnapi/hal/1.1/Conversions.h
+++ b/neuralnetworks/1.1/utils/include/nnapi/hal/1.1/Conversions.h
@@ -51,6 +51,10 @@
 nn::GeneralResult<Model> convert(const nn::Model& model);
 nn::GeneralResult<ExecutionPreference> convert(const nn::ExecutionPreference& executionPreference);
 
+nn::GeneralResult<V1_0::DeviceStatus> convert(const nn::DeviceStatus& deviceStatus);
+nn::GeneralResult<V1_0::Request> convert(const nn::Request& request);
+nn::GeneralResult<V1_0::ErrorStatus> convert(const nn::ErrorStatus& status);
+
 }  // namespace android::hardware::neuralnetworks::V1_1::utils
 
 #endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_1_CONVERSIONS_H
diff --git a/neuralnetworks/1.1/utils/src/Conversions.cpp b/neuralnetworks/1.1/utils/src/Conversions.cpp
index 359f68a..b47f25a 100644
--- a/neuralnetworks/1.1/utils/src/Conversions.cpp
+++ b/neuralnetworks/1.1/utils/src/Conversions.cpp
@@ -275,4 +275,16 @@
     return validatedConvert(executionPreference);
 }
 
+nn::GeneralResult<V1_0::DeviceStatus> convert(const nn::DeviceStatus& deviceStatus) {
+    return V1_0::utils::convert(deviceStatus);
+}
+
+nn::GeneralResult<V1_0::Request> convert(const nn::Request& request) {
+    return V1_0::utils::convert(request);
+}
+
+nn::GeneralResult<V1_0::ErrorStatus> convert(const nn::ErrorStatus& status) {
+    return V1_0::utils::convert(status);
+}
+
 }  // namespace android::hardware::neuralnetworks::V1_1::utils
diff --git a/neuralnetworks/1.1/utils/src/Device.cpp b/neuralnetworks/1.1/utils/src/Device.cpp
index b57c7f4..3197ef4 100644
--- a/neuralnetworks/1.1/utils/src/Device.cpp
+++ b/neuralnetworks/1.1/utils/src/Device.cpp
@@ -45,24 +45,21 @@
 namespace android::hardware::neuralnetworks::V1_1::utils {
 namespace {
 
-nn::GeneralResult<nn::Capabilities> initCapabilities(V1_1::IDevice* device) {
+nn::GeneralResult<nn::Capabilities> capabilitiesCallback(V1_0::ErrorStatus status,
+                                                         const Capabilities& capabilities) {
+    HANDLE_HAL_STATUS(status) << "getting capabilities failed with " << toString(status);
+    return nn::convert(capabilities);
+}
+
+nn::GeneralResult<nn::Capabilities> getCapabilitiesFrom(V1_1::IDevice* device) {
     CHECK(device != nullptr);
 
-    nn::GeneralResult<nn::Capabilities> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                 << "uninitialized";
-    const auto cb = [&result](V1_0::ErrorStatus status, const Capabilities& capabilities) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "getCapabilities_1_1 failed with " << toString(status);
-        } else {
-            result = nn::convert(capabilities);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(capabilitiesCallback);
 
     const auto ret = device->getCapabilities_1_1(cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 }  // namespace
@@ -78,7 +75,7 @@
                << "V1_1::utils::Device::create must have non-null device";
     }
 
-    auto capabilities = NN_TRY(initCapabilities(device.get()));
+    auto capabilities = NN_TRY(getCapabilitiesFrom(device.get()));
 
     auto deathHandler = NN_TRY(hal::utils::DeathHandler::create(device));
     return std::make_shared<const Device>(PrivateConstructorTag{}, std::move(name),
@@ -135,28 +132,12 @@
 
     const auto hidlModel = NN_TRY(convert(modelInShared));
 
-    nn::GeneralResult<std::vector<bool>> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                  << "uninitialized";
-    auto cb = [&result, &model](V1_0::ErrorStatus status,
-                                const hidl_vec<bool>& supportedOperations) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical)
-                     << "getSupportedOperations_1_1 failed with " << toString(status);
-        } else if (supportedOperations.size() != model.main.operations.size()) {
-            result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                     << "getSupportedOperations_1_1 returned vector of size "
-                     << supportedOperations.size() << " but expected "
-                     << model.main.operations.size();
-        } else {
-            result = supportedOperations;
-        }
-    };
+    auto cb = hal::utils::CallbackValue(V1_0::utils::supportedOperationsCallback);
 
     const auto ret = kDevice->getSupportedOperations_1_1(hidlModel, cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 nn::GeneralResult<nn::SharedPreparedModel> Device::prepareModel(
@@ -176,10 +157,7 @@
 
     const auto ret = kDevice->prepareModel_1_1(hidlModel, hidlPreference, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "prepareModel failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "model preparation failed with " << toString(status);
 
     return cb->get();
 }
diff --git a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Callbacks.h b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Callbacks.h
index 1162bc3..ba3c1ba 100644
--- a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Callbacks.h
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Callbacks.h
@@ -36,6 +36,19 @@
 
 namespace android::hardware::neuralnetworks::V1_2::utils {
 
+// Converts the results of IDevice::prepareModel* to the NN canonical format. On success, this
+// function returns with a non-null nn::SharedPreparedModel with a feature level of
+// nn::Version::ANDROID_Q. On failure, this function returns with the appropriate nn::GeneralError.
+nn::GeneralResult<nn::SharedPreparedModel> prepareModelCallback(
+        V1_0::ErrorStatus status, const sp<IPreparedModel>& preparedModel);
+
+// Converts the results of IDevice::execute* to the NN canonical format. On success, this function
+// returns with the output shapes and the timing information. On failure, this function returns with
+// the appropriate nn::ExecutionError.
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executionCallback(
+        V1_0::ErrorStatus status, const hidl_vec<OutputShape>& outputShapes, const Timing& timing);
+
+// A HIDL callback class to receive the results of IDevice::prepareModel* asynchronously.
 class PreparedModelCallback final : public IPreparedModelCallback,
                                     public hal::utils::IProtectedCallback {
   public:
@@ -51,11 +64,10 @@
     Data get();
 
   private:
-    void notifyInternal(Data result);
-
     hal::utils::TransferValue<Data> mData;
 };
 
+// A HIDL callback class to receive the results of IDevice::execute_1_2 asynchronously.
 class ExecutionCallback final : public IExecutionCallback, public hal::utils::IProtectedCallback {
   public:
     using Data = nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>;
@@ -69,8 +81,6 @@
     Data get();
 
   private:
-    void notifyInternal(Data result);
-
     hal::utils::TransferValue<Data> mData;
 };
 
diff --git a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Conversions.h b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Conversions.h
index 5dcbc0b..6fd1337 100644
--- a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Conversions.h
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Conversions.h
@@ -97,6 +97,12 @@
 nn::GeneralResult<hidl_vec<hidl_handle>> convert(const std::vector<nn::SharedHandle>& handles);
 nn::GeneralResult<hidl_vec<OutputShape>> convert(const std::vector<nn::OutputShape>& outputShapes);
 
+nn::GeneralResult<V1_0::DeviceStatus> convert(const nn::DeviceStatus& deviceStatus);
+nn::GeneralResult<V1_0::Request> convert(const nn::Request& request);
+nn::GeneralResult<V1_0::ErrorStatus> convert(const nn::ErrorStatus& status);
+nn::GeneralResult<V1_1::ExecutionPreference> convert(
+        const nn::ExecutionPreference& executionPreference);
+
 }  // namespace android::hardware::neuralnetworks::V1_2::utils
 
 #endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_CONVERSIONS_H
diff --git a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Device.h b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Device.h
index 79c3b04..b4bef5e 100644
--- a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Device.h
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Device.h
@@ -37,10 +37,21 @@
 
 namespace android::hardware::neuralnetworks::V1_2::utils {
 
-nn::GeneralResult<std::string> initVersionString(V1_2::IDevice* device);
-nn::GeneralResult<nn::DeviceType> initDeviceType(V1_2::IDevice* device);
-nn::GeneralResult<std::vector<nn::Extension>> initExtensions(V1_2::IDevice* device);
-nn::GeneralResult<std::pair<uint32_t, uint32_t>> initNumberOfCacheFilesNeeded(
+// Retrieves the version string from the provided device object. On failure, this function returns
+// with the appropriate nn::GeneralError.
+nn::GeneralResult<std::string> getVersionStringFrom(V1_2::IDevice* device);
+
+// Retrieves the device type from the provided device object. On failure, this function returns with
+// the appropriate nn::GeneralError.
+nn::GeneralResult<nn::DeviceType> getDeviceTypeFrom(V1_2::IDevice* device);
+
+// Retrieves the extensions supported by the provided device object. On failure, this function
+// returns with the appropriate nn::GeneralError.
+nn::GeneralResult<std::vector<nn::Extension>> getSupportedExtensionsFrom(V1_2::IDevice* device);
+
+// Retrieves the number of model cache files and data cache files needed by the provided device
+// object. On failure, this function returns with the appropriate nn::GeneralError.
+nn::GeneralResult<std::pair<uint32_t, uint32_t>> getNumberOfCacheFilesNeededFrom(
         V1_2::IDevice* device);
 
 // Class that adapts V1_2::IDevice to nn::IDevice.
diff --git a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/PreparedModel.h b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/PreparedModel.h
index 8ed5ca7..6a56a82 100644
--- a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/PreparedModel.h
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/PreparedModel.h
@@ -41,10 +41,10 @@
 
   public:
     static nn::GeneralResult<std::shared_ptr<const PreparedModel>> create(
-            sp<V1_2::IPreparedModel> preparedModel);
+            sp<V1_2::IPreparedModel> preparedModel, bool executeSynchronously);
 
-    PreparedModel(PrivateConstructorTag tag, sp<V1_2::IPreparedModel> preparedModel,
-                  hal::utils::DeathHandler deathHandler);
+    PreparedModel(PrivateConstructorTag tag, bool executeSynchronously,
+                  sp<V1_2::IPreparedModel> preparedModel, hal::utils::DeathHandler deathHandler);
 
     nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> execute(
             const nn::Request& request, nn::MeasureTiming measure,
@@ -65,6 +65,7 @@
     nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executeAsynchronously(
             const V1_0::Request& request, MeasureTiming measure) const;
 
+    const bool kExecuteSynchronously;
     const sp<V1_2::IPreparedModel> kPreparedModel;
     const hal::utils::DeathHandler kDeathHandler;
 };
diff --git a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Utils.h b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Utils.h
index 70149a2..c289fc8 100644
--- a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Utils.h
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Utils.h
@@ -30,6 +30,8 @@
 
 namespace android::hardware::neuralnetworks::V1_2::utils {
 
+using CacheToken = hidl_array<uint8_t, static_cast<size_t>(Constant::BYTE_SIZE_OF_CACHE_TOKEN)>;
+
 constexpr auto kDefaultMesaureTiming = MeasureTiming::NO;
 constexpr auto kNoTiming = Timing{.timeOnDevice = std::numeric_limits<uint64_t>::max(),
                                   .timeInDriver = std::numeric_limits<uint64_t>::max()};
diff --git a/neuralnetworks/1.2/utils/src/Callbacks.cpp b/neuralnetworks/1.2/utils/src/Callbacks.cpp
index ab3e0ca..fefa122 100644
--- a/neuralnetworks/1.2/utils/src/Callbacks.cpp
+++ b/neuralnetworks/1.2/utils/src/Callbacks.cpp
@@ -27,6 +27,7 @@
 #include <nnapi/IPreparedModel.h>
 #include <nnapi/Result.h>
 #include <nnapi/Types.h>
+#include <nnapi/hal/1.0/Callbacks.h>
 #include <nnapi/hal/1.0/Conversions.h>
 #include <nnapi/hal/1.0/PreparedModel.h>
 #include <nnapi/hal/CommonUtils.h>
@@ -42,104 +43,73 @@
 namespace android::hardware::neuralnetworks::V1_2::utils {
 namespace {
 
-nn::GeneralResult<nn::SharedPreparedModel> convertPreparedModel(
-        const sp<V1_0::IPreparedModel>& preparedModel) {
-    return NN_TRY(V1_0::utils::PreparedModel::create(preparedModel));
-}
-
-nn::GeneralResult<nn::SharedPreparedModel> convertPreparedModel(
-        const sp<IPreparedModel>& preparedModel) {
-    return NN_TRY(utils::PreparedModel::create(preparedModel));
-}
-
 nn::GeneralResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
 convertExecutionGeneralResultsHelper(const hidl_vec<OutputShape>& outputShapes,
                                      const Timing& timing) {
     return std::make_pair(NN_TRY(nn::convert(outputShapes)), NN_TRY(nn::convert(timing)));
 }
 
-nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
-convertExecutionGeneralResults(const hidl_vec<OutputShape>& outputShapes, const Timing& timing) {
+}  // namespace
+
+nn::GeneralResult<nn::SharedPreparedModel> prepareModelCallback(
+        V1_0::ErrorStatus status, const sp<IPreparedModel>& preparedModel) {
+    HANDLE_HAL_STATUS(status) << "model preparation failed with " << toString(status);
+    return NN_TRY(PreparedModel::create(preparedModel, /*executeSynchronously=*/true));
+}
+
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executionCallback(
+        V1_0::ErrorStatus status, const hidl_vec<OutputShape>& outputShapes, const Timing& timing) {
+    if (status == V1_0::ErrorStatus::OUTPUT_INSUFFICIENT_SIZE) {
+        auto canonicalOutputShapes =
+                nn::convert(outputShapes).value_or(std::vector<nn::OutputShape>{});
+        return NN_ERROR(nn::ErrorStatus::OUTPUT_INSUFFICIENT_SIZE, std::move(canonicalOutputShapes))
+               << "execution failed with " << toString(status);
+    }
+    HANDLE_HAL_STATUS(status) << "execution failed with " << toString(status);
     return hal::utils::makeExecutionFailure(
             convertExecutionGeneralResultsHelper(outputShapes, timing));
 }
 
-}  // namespace
-
 Return<void> PreparedModelCallback::notify(V1_0::ErrorStatus status,
                                            const sp<V1_0::IPreparedModel>& preparedModel) {
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "preparedModel failed with " << toString(status));
-    } else if (preparedModel == nullptr) {
-        notifyInternal(NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                       << "Returned preparedModel is nullptr");
-    } else {
-        notifyInternal(convertPreparedModel(preparedModel));
-    }
+    mData.put(V1_0::utils::prepareModelCallback(status, preparedModel));
     return Void();
 }
 
 Return<void> PreparedModelCallback::notify_1_2(V1_0::ErrorStatus status,
                                                const sp<IPreparedModel>& preparedModel) {
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "preparedModel failed with " << toString(status));
-    } else if (preparedModel == nullptr) {
-        notifyInternal(NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                       << "Returned preparedModel is nullptr");
-    } else {
-        notifyInternal(convertPreparedModel(preparedModel));
-    }
+    mData.put(prepareModelCallback(status, preparedModel));
     return Void();
 }
 
 void PreparedModelCallback::notifyAsDeadObject() {
-    notifyInternal(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
+    mData.put(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
 }
 
 PreparedModelCallback::Data PreparedModelCallback::get() {
     return mData.take();
 }
 
-void PreparedModelCallback::notifyInternal(PreparedModelCallback::Data result) {
-    mData.put(std::move(result));
-}
-
 // ExecutionCallback methods begin here
 
 Return<void> ExecutionCallback::notify(V1_0::ErrorStatus status) {
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "execute failed with " << toString(status));
-    } else {
-        notifyInternal({});
-    }
+    mData.put(V1_0::utils::executionCallback(status));
     return Void();
 }
 
 Return<void> ExecutionCallback::notify_1_2(V1_0::ErrorStatus status,
                                            const hidl_vec<OutputShape>& outputShapes,
                                            const Timing& timing) {
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "execute failed with " << toString(status));
-    } else {
-        notifyInternal(convertExecutionGeneralResults(outputShapes, timing));
-    }
+    mData.put(executionCallback(status, outputShapes, timing));
     return Void();
 }
 
 void ExecutionCallback::notifyAsDeadObject() {
-    notifyInternal(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
+    mData.put(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
 }
 
 ExecutionCallback::Data ExecutionCallback::get() {
     return mData.take();
 }
 
-void ExecutionCallback::notifyInternal(ExecutionCallback::Data result) {
-    mData.put(std::move(result));
-}
-
 }  // namespace android::hardware::neuralnetworks::V1_2::utils
diff --git a/neuralnetworks/1.2/utils/src/Conversions.cpp b/neuralnetworks/1.2/utils/src/Conversions.cpp
index 3790d1f..062f6f7 100644
--- a/neuralnetworks/1.2/utils/src/Conversions.cpp
+++ b/neuralnetworks/1.2/utils/src/Conversions.cpp
@@ -26,6 +26,7 @@
 #include <nnapi/Types.h>
 #include <nnapi/Validation.h>
 #include <nnapi/hal/1.0/Conversions.h>
+#include <nnapi/hal/1.1/Conversions.h>
 #include <nnapi/hal/CommonUtils.h>
 #include <nnapi/hal/HandleError.h>
 
@@ -622,4 +623,21 @@
     return validatedConvert(outputShapes);
 }
 
+nn::GeneralResult<V1_0::DeviceStatus> convert(const nn::DeviceStatus& deviceStatus) {
+    return V1_1::utils::convert(deviceStatus);
+}
+
+nn::GeneralResult<V1_0::Request> convert(const nn::Request& request) {
+    return V1_1::utils::convert(request);
+}
+
+nn::GeneralResult<V1_0::ErrorStatus> convert(const nn::ErrorStatus& status) {
+    return V1_1::utils::convert(status);
+}
+
+nn::GeneralResult<V1_1::ExecutionPreference> convert(
+        const nn::ExecutionPreference& executionPreference) {
+    return V1_1::utils::convert(executionPreference);
+}
+
 }  // namespace android::hardware::neuralnetworks::V1_2::utils
diff --git a/neuralnetworks/1.2/utils/src/Device.cpp b/neuralnetworks/1.2/utils/src/Device.cpp
index 6cca841..9fe0de2 100644
--- a/neuralnetworks/1.2/utils/src/Device.cpp
+++ b/neuralnetworks/1.2/utils/src/Device.cpp
@@ -47,109 +47,102 @@
 namespace android::hardware::neuralnetworks::V1_2::utils {
 namespace {
 
-nn::GeneralResult<nn::Capabilities> initCapabilities(V1_2::IDevice* device) {
+nn::GeneralResult<nn::Capabilities> capabilitiesCallback(V1_0::ErrorStatus status,
+                                                         const Capabilities& capabilities) {
+    HANDLE_HAL_STATUS(status) << "getting capabilities failed with " << toString(status);
+    return nn::convert(capabilities);
+}
+
+nn::GeneralResult<std::string> versionStringCallback(V1_0::ErrorStatus status,
+                                                     const hidl_string& versionString) {
+    HANDLE_HAL_STATUS(status) << "getVersionString failed with " << toString(status);
+    return versionString;
+}
+
+nn::GeneralResult<nn::DeviceType> deviceTypeCallback(V1_0::ErrorStatus status,
+                                                     DeviceType deviceType) {
+    HANDLE_HAL_STATUS(status) << "getDeviceType failed with " << toString(status);
+    return nn::convert(deviceType);
+}
+
+nn::GeneralResult<std::vector<nn::Extension>> supportedExtensionsCallback(
+        V1_0::ErrorStatus status, const hidl_vec<Extension>& extensions) {
+    HANDLE_HAL_STATUS(status) << "getExtensions failed with " << toString(status);
+    return nn::convert(extensions);
+}
+
+nn::GeneralResult<std::pair<uint32_t, uint32_t>> numberOfCacheFilesNeededCallback(
+        V1_0::ErrorStatus status, uint32_t numModelCache, uint32_t numDataCache) {
+    HANDLE_HAL_STATUS(status) << "getNumberOfCacheFilesNeeded failed with " << toString(status);
+    if (numModelCache > nn::kMaxNumberOfCacheFiles) {
+        return NN_ERROR() << "getNumberOfCacheFilesNeeded returned numModelCache files greater "
+                             "than allowed max ("
+                          << numModelCache << " vs " << nn::kMaxNumberOfCacheFiles << ")";
+    }
+    if (numDataCache > nn::kMaxNumberOfCacheFiles) {
+        return NN_ERROR() << "getNumberOfCacheFilesNeeded returned numDataCache files greater "
+                             "than allowed max ("
+                          << numDataCache << " vs " << nn::kMaxNumberOfCacheFiles << ")";
+    }
+    return std::make_pair(numModelCache, numDataCache);
+}
+
+nn::GeneralResult<nn::Capabilities> getCapabilitiesFrom(V1_2::IDevice* device) {
     CHECK(device != nullptr);
 
-    nn::GeneralResult<nn::Capabilities> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                 << "uninitialized";
-    const auto cb = [&result](V1_0::ErrorStatus status, const Capabilities& capabilities) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "getCapabilities_1_2 failed with " << toString(status);
-        } else {
-            result = nn::convert(capabilities);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(capabilitiesCallback);
 
     const auto ret = device->getCapabilities_1_2(cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 }  // namespace
 
-nn::GeneralResult<std::string> initVersionString(V1_2::IDevice* device) {
+nn::GeneralResult<std::string> getVersionStringFrom(V1_2::IDevice* device) {
     CHECK(device != nullptr);
 
-    nn::GeneralResult<std::string> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                            << "uninitialized";
-    const auto cb = [&result](V1_0::ErrorStatus status, const hidl_string& versionString) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "getVersionString failed with " << toString(status);
-        } else {
-            result = versionString;
-        }
-    };
+    auto cb = hal::utils::CallbackValue(versionStringCallback);
 
     const auto ret = device->getVersionString(cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
-nn::GeneralResult<nn::DeviceType> initDeviceType(V1_2::IDevice* device) {
+nn::GeneralResult<nn::DeviceType> getDeviceTypeFrom(V1_2::IDevice* device) {
     CHECK(device != nullptr);
 
-    nn::GeneralResult<nn::DeviceType> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                               << "uninitialized";
-    const auto cb = [&result](V1_0::ErrorStatus status, DeviceType deviceType) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "getDeviceType failed with " << toString(status);
-        } else {
-            result = nn::convert(deviceType);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(deviceTypeCallback);
 
     const auto ret = device->getType(cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
-nn::GeneralResult<std::vector<nn::Extension>> initExtensions(V1_2::IDevice* device) {
+nn::GeneralResult<std::vector<nn::Extension>> getSupportedExtensionsFrom(V1_2::IDevice* device) {
     CHECK(device != nullptr);
 
-    nn::GeneralResult<std::vector<nn::Extension>> result =
-            NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "uninitialized";
-    const auto cb = [&result](V1_0::ErrorStatus status, const hidl_vec<Extension>& extensions) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "getExtensions failed with " << toString(status);
-        } else {
-            result = nn::convert(extensions);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(supportedExtensionsCallback);
 
     const auto ret = device->getSupportedExtensions(cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
-nn::GeneralResult<std::pair<uint32_t, uint32_t>> initNumberOfCacheFilesNeeded(
+nn::GeneralResult<std::pair<uint32_t, uint32_t>> getNumberOfCacheFilesNeededFrom(
         V1_2::IDevice* device) {
     CHECK(device != nullptr);
 
-    nn::GeneralResult<std::pair<uint32_t, uint32_t>> result =
-            NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "uninitialized";
-    const auto cb = [&result](V1_0::ErrorStatus status, uint32_t numModelCache,
-                              uint32_t numDataCache) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical)
-                     << "getNumberOfCacheFilesNeeded failed with " << toString(status);
-        } else {
-            result = std::make_pair(numModelCache, numDataCache);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(numberOfCacheFilesNeededCallback);
 
     const auto ret = device->getNumberOfCacheFilesNeeded(cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 nn::GeneralResult<std::shared_ptr<const Device>> Device::create(std::string name,
@@ -163,11 +156,11 @@
                << "V1_2::utils::Device::create must have non-null device";
     }
 
-    auto versionString = NN_TRY(initVersionString(device.get()));
-    const auto deviceType = NN_TRY(initDeviceType(device.get()));
-    auto extensions = NN_TRY(initExtensions(device.get()));
-    auto capabilities = NN_TRY(initCapabilities(device.get()));
-    const auto numberOfCacheFilesNeeded = NN_TRY(initNumberOfCacheFilesNeeded(device.get()));
+    auto versionString = NN_TRY(getVersionStringFrom(device.get()));
+    const auto deviceType = NN_TRY(getDeviceTypeFrom(device.get()));
+    auto extensions = NN_TRY(getSupportedExtensionsFrom(device.get()));
+    auto capabilities = NN_TRY(getCapabilitiesFrom(device.get()));
+    const auto numberOfCacheFilesNeeded = NN_TRY(getNumberOfCacheFilesNeededFrom(device.get()));
 
     auto deathHandler = NN_TRY(hal::utils::DeathHandler::create(device));
     return std::make_shared<const Device>(
@@ -232,28 +225,12 @@
 
     const auto hidlModel = NN_TRY(convert(modelInShared));
 
-    nn::GeneralResult<std::vector<bool>> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                  << "uninitialized";
-    auto cb = [&result, &model](V1_0::ErrorStatus status,
-                                const hidl_vec<bool>& supportedOperations) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical)
-                     << "getSupportedOperations_1_2 failed with " << toString(status);
-        } else if (supportedOperations.size() != model.main.operations.size()) {
-            result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                     << "getSupportedOperations_1_2 returned vector of size "
-                     << supportedOperations.size() << " but expected "
-                     << model.main.operations.size();
-        } else {
-            result = supportedOperations;
-        }
-    };
+    auto cb = hal::utils::CallbackValue(V1_0::utils::supportedOperationsCallback);
 
     const auto ret = kDevice->getSupportedOperations_1_2(hidlModel, cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 nn::GeneralResult<nn::SharedPreparedModel> Device::prepareModel(
@@ -266,10 +243,10 @@
             NN_TRY(hal::utils::flushDataFromPointerToShared(&model, &maybeModelInShared));
 
     const auto hidlModel = NN_TRY(convert(modelInShared));
-    const auto hidlPreference = NN_TRY(V1_1::utils::convert(preference));
+    const auto hidlPreference = NN_TRY(convert(preference));
     const auto hidlModelCache = NN_TRY(convert(modelCache));
     const auto hidlDataCache = NN_TRY(convert(dataCache));
-    const auto hidlToken = token;
+    const auto hidlToken = CacheToken{token};
 
     const auto cb = sp<PreparedModelCallback>::make();
     const auto scoped = kDeathHandler.protectCallback(cb.get());
@@ -277,10 +254,7 @@
     const auto ret = kDevice->prepareModel_1_2(hidlModel, hidlPreference, hidlModelCache,
                                                hidlDataCache, hidlToken, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "prepareModel_1_2 failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "model preparation failed with " << toString(status);
 
     return cb->get();
 }
@@ -290,17 +264,14 @@
         const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const {
     const auto hidlModelCache = NN_TRY(convert(modelCache));
     const auto hidlDataCache = NN_TRY(convert(dataCache));
-    const auto hidlToken = token;
+    const auto hidlToken = CacheToken{token};
 
     const auto cb = sp<PreparedModelCallback>::make();
     const auto scoped = kDeathHandler.protectCallback(cb.get());
 
     const auto ret = kDevice->prepareModelFromCache(hidlModelCache, hidlDataCache, hidlToken, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "prepareModelFromCache failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "model preparation from cache failed with " << toString(status);
 
     return cb->get();
 }
diff --git a/neuralnetworks/1.2/utils/src/PreparedModel.cpp b/neuralnetworks/1.2/utils/src/PreparedModel.cpp
index b422ced..6d00082 100644
--- a/neuralnetworks/1.2/utils/src/PreparedModel.cpp
+++ b/neuralnetworks/1.2/utils/src/PreparedModel.cpp
@@ -41,54 +41,33 @@
 // lifetimes across processes and for protecting asynchronous calls across HIDL.
 
 namespace android::hardware::neuralnetworks::V1_2::utils {
-namespace {
-
-nn::GeneralResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
-convertExecutionResultsHelper(const hidl_vec<OutputShape>& outputShapes, const Timing& timing) {
-    return std::make_pair(NN_TRY(nn::convert(outputShapes)), NN_TRY(nn::convert(timing)));
-}
-
-nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> convertExecutionResults(
-        const hidl_vec<OutputShape>& outputShapes, const Timing& timing) {
-    return hal::utils::makeExecutionFailure(convertExecutionResultsHelper(outputShapes, timing));
-}
-
-}  // namespace
 
 nn::GeneralResult<std::shared_ptr<const PreparedModel>> PreparedModel::create(
-        sp<V1_2::IPreparedModel> preparedModel) {
+        sp<V1_2::IPreparedModel> preparedModel, bool executeSynchronously) {
     if (preparedModel == nullptr) {
-        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
-               << "V1_2::utils::PreparedModel::create must have non-null preparedModel";
+        return NN_ERROR() << "V1_2::utils::PreparedModel::create must have non-null preparedModel";
     }
 
     auto deathHandler = NN_TRY(hal::utils::DeathHandler::create(preparedModel));
-    return std::make_shared<const PreparedModel>(PrivateConstructorTag{}, std::move(preparedModel),
-                                                 std::move(deathHandler));
+    return std::make_shared<const PreparedModel>(PrivateConstructorTag{}, executeSynchronously,
+                                                 std::move(preparedModel), std::move(deathHandler));
 }
 
-PreparedModel::PreparedModel(PrivateConstructorTag /*tag*/, sp<V1_2::IPreparedModel> preparedModel,
+PreparedModel::PreparedModel(PrivateConstructorTag /*tag*/, bool executeSynchronously,
+                             sp<V1_2::IPreparedModel> preparedModel,
                              hal::utils::DeathHandler deathHandler)
-    : kPreparedModel(std::move(preparedModel)), kDeathHandler(std::move(deathHandler)) {}
+    : kExecuteSynchronously(executeSynchronously),
+      kPreparedModel(std::move(preparedModel)),
+      kDeathHandler(std::move(deathHandler)) {}
 
 nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
 PreparedModel::executeSynchronously(const V1_0::Request& request, MeasureTiming measure) const {
-    nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> result =
-            NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "uninitialized";
-    const auto cb = [&result](V1_0::ErrorStatus status, const hidl_vec<OutputShape>& outputShapes,
-                              const Timing& timing) {
-        if (status != V1_0::ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "executeSynchronously failed with " << toString(status);
-        } else {
-            result = convertExecutionResults(outputShapes, timing);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(executionCallback);
 
     const auto ret = kPreparedModel->executeSynchronously(request, measure, cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
@@ -98,9 +77,8 @@
 
     const auto ret = kPreparedModel->execute_1_2(request, measure, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "execute failed with " << toString(status);
+    if (status != V1_0::ErrorStatus::OUTPUT_INSUFFICIENT_SIZE) {
+        HANDLE_HAL_STATUS(status) << "execution failed with " << toString(status);
     }
 
     return cb->get();
@@ -115,31 +93,17 @@
     const nn::Request& requestInShared = NN_TRY(hal::utils::makeExecutionFailure(
             hal::utils::flushDataFromPointerToShared(&request, &maybeRequestInShared)));
 
-    const auto hidlRequest =
-            NN_TRY(hal::utils::makeExecutionFailure(V1_0::utils::convert(requestInShared)));
+    const auto hidlRequest = NN_TRY(hal::utils::makeExecutionFailure(convert(requestInShared)));
     const auto hidlMeasure = NN_TRY(hal::utils::makeExecutionFailure(convert(measure)));
 
-    nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> result =
-            NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "uninitialized";
-    const bool preferSynchronous = true;
+    auto result = kExecuteSynchronously ? executeSynchronously(hidlRequest, hidlMeasure)
+                                        : executeAsynchronously(hidlRequest, hidlMeasure);
+    auto [outputShapes, timing] = NN_TRY(std::move(result));
 
-    // Execute synchronously if allowed.
-    if (preferSynchronous) {
-        result = executeSynchronously(hidlRequest, hidlMeasure);
-    }
+    NN_TRY(hal::utils::makeExecutionFailure(
+            hal::utils::unflushDataFromSharedToPointer(request, maybeRequestInShared)));
 
-    // Run asymchronous execution if execution has not already completed.
-    if (!result.has_value()) {
-        result = executeAsynchronously(hidlRequest, hidlMeasure);
-    }
-
-    // Flush output buffers if suxcessful execution.
-    if (result.has_value()) {
-        NN_TRY(hal::utils::makeExecutionFailure(
-                hal::utils::unflushDataFromSharedToPointer(request, maybeRequestInShared)));
-    }
-
-    return result;
+    return std::make_pair(std::move(outputShapes), timing);
 }
 
 nn::GeneralResult<std::pair<nn::SyncFence, nn::ExecuteFencedInfoCallback>>
@@ -154,7 +118,7 @@
 }
 
 std::any PreparedModel::getUnderlyingResource() const {
-    sp<V1_0::IPreparedModel> resource = kPreparedModel;
+    sp<V1_2::IPreparedModel> resource = kPreparedModel;
     return resource;
 }
 
diff --git a/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/Callbacks.h b/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/Callbacks.h
index cb2a56a..643172e 100644
--- a/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/Callbacks.h
+++ b/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/Callbacks.h
@@ -39,6 +39,26 @@
 
 namespace android::hardware::neuralnetworks::V1_3::utils {
 
+// Converts the results of IDevice::getSupportedOperations* to the NN canonical format. On success,
+// this function returns with the supported operations as indicated by a driver. On failure, this
+// function returns with the appropriate nn::GeneralError.
+nn::GeneralResult<std::vector<bool>> supportedOperationsCallback(
+        ErrorStatus status, const hidl_vec<bool>& supportedOperations);
+
+// Converts the results of IDevice::prepareModel* to the NN canonical format. On success, this
+// function returns with a non-null nn::SharedPreparedModel with a feature level of
+// nn::Version::ANDROID_R. On failure, this function returns with the appropriate nn::GeneralError.
+nn::GeneralResult<nn::SharedPreparedModel> prepareModelCallback(
+        ErrorStatus status, const sp<IPreparedModel>& preparedModel);
+
+// Converts the results of IDevice::execute* to the NN canonical format. On success, this function
+// returns with the output shapes and the timing information. On failure, this function returns with
+// the appropriate nn::ExecutionError.
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executionCallback(
+        ErrorStatus status, const hidl_vec<V1_2::OutputShape>& outputShapes,
+        const V1_2::Timing& timing);
+
+// A HIDL callback class to receive the results of IDevice::prepareModel* asynchronously.
 class PreparedModelCallback final : public IPreparedModelCallback,
                                     public hal::utils::IProtectedCallback {
   public:
@@ -55,11 +75,10 @@
     Data get();
 
   private:
-    void notifyInternal(Data result);
-
     hal::utils::TransferValue<Data> mData;
 };
 
+// A HIDL callback class to receive the results of IDevice::execute_1_3 asynchronously.
 class ExecutionCallback final : public IExecutionCallback, public hal::utils::IProtectedCallback {
   public:
     using Data = nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>;
@@ -76,8 +95,6 @@
     Data get();
 
   private:
-    void notifyInternal(Data result);
-
     hal::utils::TransferValue<Data> mData;
 };
 
diff --git a/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/Conversions.h b/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/Conversions.h
index 477bb7b..74a6534 100644
--- a/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/Conversions.h
+++ b/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/Conversions.h
@@ -103,6 +103,17 @@
 nn::GeneralResult<hidl_memory> convert(const nn::Memory& memory);
 nn::GeneralResult<hidl_vec<BufferRole>> convert(const std::vector<nn::BufferRole>& bufferRoles);
 
+nn::GeneralResult<V1_0::DeviceStatus> convert(const nn::DeviceStatus& deviceStatus);
+nn::GeneralResult<V1_1::ExecutionPreference> convert(
+        const nn::ExecutionPreference& executionPreference);
+nn::GeneralResult<hidl_vec<V1_2::Extension>> convert(const std::vector<nn::Extension>& extensions);
+nn::GeneralResult<hidl_vec<hidl_handle>> convert(const std::vector<nn::SharedHandle>& handles);
+nn::GeneralResult<hidl_vec<V1_2::OutputShape>> convert(
+        const std::vector<nn::OutputShape>& outputShapes);
+nn::GeneralResult<V1_2::DeviceType> convert(const nn::DeviceType& deviceType);
+nn::GeneralResult<V1_2::MeasureTiming> convert(const nn::MeasureTiming& measureTiming);
+nn::GeneralResult<V1_2::Timing> convert(const nn::Timing& timing);
+
 }  // namespace android::hardware::neuralnetworks::V1_3::utils
 
 #endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_3_CONVERSIONS_H
diff --git a/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/PreparedModel.h b/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/PreparedModel.h
index c4ba483..664d87a 100644
--- a/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/PreparedModel.h
+++ b/neuralnetworks/1.3/utils/include/nnapi/hal/1.3/PreparedModel.h
@@ -40,10 +40,10 @@
 
   public:
     static nn::GeneralResult<std::shared_ptr<const PreparedModel>> create(
-            sp<V1_3::IPreparedModel> preparedModel);
+            sp<V1_3::IPreparedModel> preparedModel, bool executeSynchronously);
 
-    PreparedModel(PrivateConstructorTag tag, sp<V1_3::IPreparedModel> preparedModel,
-                  hal::utils::DeathHandler deathHandler);
+    PreparedModel(PrivateConstructorTag tag, bool executeSynchronously,
+                  sp<V1_3::IPreparedModel> preparedModel, hal::utils::DeathHandler deathHandler);
 
     nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> execute(
             const nn::Request& request, nn::MeasureTiming measure,
@@ -66,6 +66,7 @@
             const Request& request, V1_2::MeasureTiming measure, const OptionalTimePoint& deadline,
             const OptionalTimeoutDuration& loopTimeoutDuration) const;
 
+    const bool kExecuteSynchronously;
     const sp<V1_3::IPreparedModel> kPreparedModel;
     const hal::utils::DeathHandler kDeathHandler;
 };
diff --git a/neuralnetworks/1.3/utils/src/Buffer.cpp b/neuralnetworks/1.3/utils/src/Buffer.cpp
index 4ef54a2..614033e 100644
--- a/neuralnetworks/1.3/utils/src/Buffer.cpp
+++ b/neuralnetworks/1.3/utils/src/Buffer.cpp
@@ -41,12 +41,10 @@
 nn::GeneralResult<std::shared_ptr<const Buffer>> Buffer::create(
         sp<V1_3::IBuffer> buffer, nn::Request::MemoryDomainToken token) {
     if (buffer == nullptr) {
-        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
-               << "V1_3::utils::Buffer::create must have non-null buffer";
+        return NN_ERROR() << "V1_3::utils::Buffer::create must have non-null buffer";
     }
     if (token == static_cast<nn::Request::MemoryDomainToken>(0)) {
-        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
-               << "V1_3::utils::Buffer::create must have non-zero token";
+        return NN_ERROR() << "V1_3::utils::Buffer::create must have non-zero token";
     }
 
     return std::make_shared<const Buffer>(PrivateConstructorTag{}, std::move(buffer), token);
@@ -68,10 +66,7 @@
 
     const auto ret = kBuffer->copyTo(hidlDst);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "IBuffer::copyTo failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "IBuffer::copyTo failed with " << toString(status);
 
     return {};
 }
@@ -83,10 +78,7 @@
 
     const auto ret = kBuffer->copyFrom(hidlSrc, hidlDimensions);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "IBuffer::copyFrom failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "IBuffer::copyFrom failed with " << toString(status);
 
     return {};
 }
diff --git a/neuralnetworks/1.3/utils/src/Callbacks.cpp b/neuralnetworks/1.3/utils/src/Callbacks.cpp
index 17c20fb..af76e6a 100644
--- a/neuralnetworks/1.3/utils/src/Callbacks.cpp
+++ b/neuralnetworks/1.3/utils/src/Callbacks.cpp
@@ -30,6 +30,7 @@
 #include <nnapi/Types.h>
 #include <nnapi/hal/1.0/Conversions.h>
 #include <nnapi/hal/1.0/PreparedModel.h>
+#include <nnapi/hal/1.2/Callbacks.h>
 #include <nnapi/hal/1.2/Conversions.h>
 #include <nnapi/hal/1.2/PreparedModel.h>
 #include <nnapi/hal/CommonUtils.h>
@@ -45,136 +46,93 @@
 namespace android::hardware::neuralnetworks::V1_3::utils {
 namespace {
 
-nn::GeneralResult<nn::SharedPreparedModel> convertPreparedModel(
-        const sp<V1_0::IPreparedModel>& preparedModel) {
-    return NN_TRY(V1_0::utils::PreparedModel::create(preparedModel));
-}
-
-nn::GeneralResult<nn::SharedPreparedModel> convertPreparedModel(
-        const sp<V1_2::IPreparedModel>& preparedModel) {
-    return NN_TRY(V1_2::utils::PreparedModel::create(preparedModel));
-}
-
-nn::GeneralResult<nn::SharedPreparedModel> convertPreparedModel(
-        const sp<IPreparedModel>& preparedModel) {
-    return NN_TRY(utils::PreparedModel::create(preparedModel));
-}
-
 nn::GeneralResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
 convertExecutionGeneralResultsHelper(const hidl_vec<V1_2::OutputShape>& outputShapes,
                                      const V1_2::Timing& timing) {
     return std::make_pair(NN_TRY(nn::convert(outputShapes)), NN_TRY(nn::convert(timing)));
 }
 
-nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
-convertExecutionGeneralResults(const hidl_vec<V1_2::OutputShape>& outputShapes,
-                               const V1_2::Timing& timing) {
+}  // namespace
+
+nn::GeneralResult<std::vector<bool>> supportedOperationsCallback(
+        ErrorStatus status, const hidl_vec<bool>& supportedOperations) {
+    HANDLE_HAL_STATUS(status) << "get supported operations failed with " << toString(status);
+    return supportedOperations;
+}
+
+nn::GeneralResult<nn::SharedPreparedModel> prepareModelCallback(
+        ErrorStatus status, const sp<IPreparedModel>& preparedModel) {
+    HANDLE_HAL_STATUS(status) << "model preparation failed with " << toString(status);
+    return NN_TRY(PreparedModel::create(preparedModel, /*executeSynchronously=*/true));
+}
+
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executionCallback(
+        ErrorStatus status, const hidl_vec<V1_2::OutputShape>& outputShapes,
+        const V1_2::Timing& timing) {
+    if (status == ErrorStatus::OUTPUT_INSUFFICIENT_SIZE) {
+        auto canonicalOutputShapes =
+                nn::convert(outputShapes).value_or(std::vector<nn::OutputShape>{});
+        return NN_ERROR(nn::ErrorStatus::OUTPUT_INSUFFICIENT_SIZE, std::move(canonicalOutputShapes))
+               << "execution failed with " << toString(status);
+    }
+    HANDLE_HAL_STATUS(status) << "execution failed with " << toString(status);
     return hal::utils::makeExecutionFailure(
             convertExecutionGeneralResultsHelper(outputShapes, timing));
 }
 
-}  // namespace
-
 Return<void> PreparedModelCallback::notify(V1_0::ErrorStatus status,
                                            const sp<V1_0::IPreparedModel>& preparedModel) {
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "preparedModel failed with " << toString(status));
-    } else if (preparedModel == nullptr) {
-        notifyInternal(NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                       << "Returned preparedModel is nullptr");
-    } else {
-        notifyInternal(convertPreparedModel(preparedModel));
-    }
+    mData.put(V1_0::utils::prepareModelCallback(status, preparedModel));
     return Void();
 }
 
 Return<void> PreparedModelCallback::notify_1_2(V1_0::ErrorStatus status,
                                                const sp<V1_2::IPreparedModel>& preparedModel) {
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "preparedModel failed with " << toString(status));
-    } else if (preparedModel == nullptr) {
-        notifyInternal(NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                       << "Returned preparedModel is nullptr");
-    } else {
-        notifyInternal(convertPreparedModel(preparedModel));
-    }
+    mData.put(V1_2::utils::prepareModelCallback(status, preparedModel));
     return Void();
 }
 
 Return<void> PreparedModelCallback::notify_1_3(ErrorStatus status,
                                                const sp<IPreparedModel>& preparedModel) {
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "preparedModel failed with " << toString(status));
-    } else if (preparedModel == nullptr) {
-        notifyInternal(NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                       << "Returned preparedModel is nullptr");
-    } else {
-        notifyInternal(convertPreparedModel(preparedModel));
-    }
+    mData.put(prepareModelCallback(status, preparedModel));
     return Void();
 }
 
 void PreparedModelCallback::notifyAsDeadObject() {
-    notifyInternal(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
+    mData.put(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
 }
 
 PreparedModelCallback::Data PreparedModelCallback::get() {
     return mData.take();
 }
 
-void PreparedModelCallback::notifyInternal(PreparedModelCallback::Data result) {
-    mData.put(std::move(result));
-}
-
 // ExecutionCallback methods begin here
 
 Return<void> ExecutionCallback::notify(V1_0::ErrorStatus status) {
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "execute failed with " << toString(status));
-    } else {
-        notifyInternal({});
-    }
+    mData.put(V1_0::utils::executionCallback(status));
     return Void();
 }
 
 Return<void> ExecutionCallback::notify_1_2(V1_0::ErrorStatus status,
                                            const hidl_vec<V1_2::OutputShape>& outputShapes,
                                            const V1_2::Timing& timing) {
-    if (status != V1_0::ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "execute failed with " << toString(status));
-    } else {
-        notifyInternal(convertExecutionGeneralResults(outputShapes, timing));
-    }
+    mData.put(V1_2::utils::executionCallback(status, outputShapes, timing));
     return Void();
 }
 
 Return<void> ExecutionCallback::notify_1_3(ErrorStatus status,
                                            const hidl_vec<V1_2::OutputShape>& outputShapes,
                                            const V1_2::Timing& timing) {
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        notifyInternal(NN_ERROR(canonical) << "execute failed with " << toString(status));
-    } else {
-        notifyInternal(convertExecutionGeneralResults(outputShapes, timing));
-    }
+    mData.put(executionCallback(status, outputShapes, timing));
     return Void();
 }
 
 void ExecutionCallback::notifyAsDeadObject() {
-    notifyInternal(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
+    mData.put(NN_ERROR(nn::ErrorStatus::DEAD_OBJECT) << "Dead object");
 }
 
 ExecutionCallback::Data ExecutionCallback::get() {
     return mData.take();
 }
 
-void ExecutionCallback::notifyInternal(ExecutionCallback::Data result) {
-    mData.put(std::move(result));
-}
-
 }  // namespace android::hardware::neuralnetworks::V1_3::utils
diff --git a/neuralnetworks/1.3/utils/src/Conversions.cpp b/neuralnetworks/1.3/utils/src/Conversions.cpp
index c89a69f..8b7db2b 100644
--- a/neuralnetworks/1.3/utils/src/Conversions.cpp
+++ b/neuralnetworks/1.3/utils/src/Conversions.cpp
@@ -685,4 +685,38 @@
     return validatedConvert(bufferRoles);
 }
 
+nn::GeneralResult<V1_0::DeviceStatus> convert(const nn::DeviceStatus& deviceStatus) {
+    return V1_2::utils::convert(deviceStatus);
+}
+
+nn::GeneralResult<V1_1::ExecutionPreference> convert(
+        const nn::ExecutionPreference& executionPreference) {
+    return V1_2::utils::convert(executionPreference);
+}
+
+nn::GeneralResult<hidl_vec<V1_2::Extension>> convert(const std::vector<nn::Extension>& extensions) {
+    return V1_2::utils::convert(extensions);
+}
+
+nn::GeneralResult<hidl_vec<hidl_handle>> convert(const std::vector<nn::SharedHandle>& handles) {
+    return V1_2::utils::convert(handles);
+}
+
+nn::GeneralResult<hidl_vec<V1_2::OutputShape>> convert(
+        const std::vector<nn::OutputShape>& outputShapes) {
+    return V1_2::utils::convert(outputShapes);
+}
+
+nn::GeneralResult<V1_2::DeviceType> convert(const nn::DeviceType& deviceType) {
+    return V1_2::utils::convert(deviceType);
+}
+
+nn::GeneralResult<V1_2::MeasureTiming> convert(const nn::MeasureTiming& measureTiming) {
+    return V1_2::utils::convert(measureTiming);
+}
+
+nn::GeneralResult<V1_2::Timing> convert(const nn::Timing& timing) {
+    return V1_2::utils::convert(timing);
+}
+
 }  // namespace android::hardware::neuralnetworks::V1_3::utils
diff --git a/neuralnetworks/1.3/utils/src/Device.cpp b/neuralnetworks/1.3/utils/src/Device.cpp
index 6056498..d710b85 100644
--- a/neuralnetworks/1.3/utils/src/Device.cpp
+++ b/neuralnetworks/1.3/utils/src/Device.cpp
@@ -36,6 +36,7 @@
 #include <nnapi/hal/1.1/Conversions.h>
 #include <nnapi/hal/1.2/Conversions.h>
 #include <nnapi/hal/1.2/Device.h>
+#include <nnapi/hal/1.2/Utils.h>
 #include <nnapi/hal/CommonUtils.h>
 #include <nnapi/hal/HandleError.h>
 #include <nnapi/hal/ProtectCallback.h>
@@ -69,29 +70,27 @@
     return hidlPreparedModels;
 }
 
-nn::GeneralResult<nn::SharedBuffer> convert(
-        nn::GeneralResult<std::shared_ptr<const Buffer>> result) {
-    return NN_TRY(std::move(result));
+nn::GeneralResult<nn::Capabilities> capabilitiesCallback(ErrorStatus status,
+                                                         const Capabilities& capabilities) {
+    HANDLE_HAL_STATUS(status) << "getting capabilities failed with " << toString(status);
+    return nn::convert(capabilities);
 }
 
-nn::GeneralResult<nn::Capabilities> initCapabilities(V1_3::IDevice* device) {
+nn::GeneralResult<nn::Capabilities> getCapabilitiesFrom(V1_3::IDevice* device) {
     CHECK(device != nullptr);
 
-    nn::GeneralResult<nn::Capabilities> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                 << "uninitialized";
-    const auto cb = [&result](ErrorStatus status, const Capabilities& capabilities) {
-        if (status != ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "getCapabilities_1_3 failed with " << toString(status);
-        } else {
-            result = nn::convert(capabilities);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(capabilitiesCallback);
 
     const auto ret = device->getCapabilities_1_3(cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
+}
+
+nn::GeneralResult<nn::SharedBuffer> allocationCallback(ErrorStatus status,
+                                                       const sp<IBuffer>& buffer, uint32_t token) {
+    HANDLE_HAL_STATUS(status) << "IDevice::allocate failed with " << toString(status);
+    return Buffer::create(buffer, static_cast<nn::Request::MemoryDomainToken>(token));
 }
 
 }  // namespace
@@ -107,12 +106,12 @@
                << "V1_3::utils::Device::create must have non-null device";
     }
 
-    auto versionString = NN_TRY(V1_2::utils::initVersionString(device.get()));
-    const auto deviceType = NN_TRY(V1_2::utils::initDeviceType(device.get()));
-    auto extensions = NN_TRY(V1_2::utils::initExtensions(device.get()));
-    auto capabilities = NN_TRY(initCapabilities(device.get()));
+    auto versionString = NN_TRY(V1_2::utils::getVersionStringFrom(device.get()));
+    const auto deviceType = NN_TRY(V1_2::utils::getDeviceTypeFrom(device.get()));
+    auto extensions = NN_TRY(V1_2::utils::getSupportedExtensionsFrom(device.get()));
+    auto capabilities = NN_TRY(getCapabilitiesFrom(device.get()));
     const auto numberOfCacheFilesNeeded =
-            NN_TRY(V1_2::utils::initNumberOfCacheFilesNeeded(device.get()));
+            NN_TRY(V1_2::utils::getNumberOfCacheFilesNeededFrom(device.get()));
 
     auto deathHandler = NN_TRY(hal::utils::DeathHandler::create(device));
     return std::make_shared<const Device>(
@@ -177,27 +176,12 @@
 
     const auto hidlModel = NN_TRY(convert(modelInShared));
 
-    nn::GeneralResult<std::vector<bool>> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                  << "uninitialized";
-    auto cb = [&result, &model](ErrorStatus status, const hidl_vec<bool>& supportedOperations) {
-        if (status != ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical)
-                     << "IDevice::getSupportedOperations_1_3 failed with " << toString(status);
-        } else if (supportedOperations.size() != model.main.operations.size()) {
-            result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                     << "IDevice::getSupportedOperations_1_3 returned vector of size "
-                     << supportedOperations.size() << " but expected "
-                     << model.main.operations.size();
-        } else {
-            result = supportedOperations;
-        }
-    };
+    auto cb = hal::utils::CallbackValue(supportedOperationsCallback);
 
     const auto ret = kDevice->getSupportedOperations_1_3(hidlModel, cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 nn::GeneralResult<nn::SharedPreparedModel> Device::prepareModel(
@@ -210,12 +194,12 @@
             NN_TRY(hal::utils::flushDataFromPointerToShared(&model, &maybeModelInShared));
 
     const auto hidlModel = NN_TRY(convert(modelInShared));
-    const auto hidlPreference = NN_TRY(V1_1::utils::convert(preference));
+    const auto hidlPreference = NN_TRY(convert(preference));
     const auto hidlPriority = NN_TRY(convert(priority));
     const auto hidlDeadline = NN_TRY(convert(deadline));
-    const auto hidlModelCache = NN_TRY(V1_2::utils::convert(modelCache));
-    const auto hidlDataCache = NN_TRY(V1_2::utils::convert(dataCache));
-    const auto hidlToken = token;
+    const auto hidlModelCache = NN_TRY(convert(modelCache));
+    const auto hidlDataCache = NN_TRY(convert(dataCache));
+    const auto hidlToken = V1_2::utils::CacheToken{token};
 
     const auto cb = sp<PreparedModelCallback>::make();
     const auto scoped = kDeathHandler.protectCallback(cb.get());
@@ -224,10 +208,7 @@
             kDevice->prepareModel_1_3(hidlModel, hidlPreference, hidlPriority, hidlDeadline,
                                       hidlModelCache, hidlDataCache, hidlToken, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "prepareModel_1_3 failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "model preparation failed with " << toString(status);
 
     return cb->get();
 }
@@ -236,9 +217,9 @@
         nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
         const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const {
     const auto hidlDeadline = NN_TRY(convert(deadline));
-    const auto hidlModelCache = NN_TRY(V1_2::utils::convert(modelCache));
-    const auto hidlDataCache = NN_TRY(V1_2::utils::convert(dataCache));
-    const auto hidlToken = token;
+    const auto hidlModelCache = NN_TRY(convert(modelCache));
+    const auto hidlDataCache = NN_TRY(convert(dataCache));
+    const auto hidlToken = V1_2::utils::CacheToken{token};
 
     const auto cb = sp<PreparedModelCallback>::make();
     const auto scoped = kDeathHandler.protectCallback(cb.get());
@@ -246,10 +227,7 @@
     const auto ret = kDevice->prepareModelFromCache_1_3(hidlDeadline, hidlModelCache, hidlDataCache,
                                                         hidlToken, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "prepareModelFromCache_1_3 failed with " << toString(status);
-    }
+    HANDLE_HAL_STATUS(status) << "model preparation from cache failed with " << toString(status);
 
     return cb->get();
 }
@@ -263,27 +241,13 @@
     const auto hidlInputRoles = NN_TRY(convert(inputRoles));
     const auto hidlOutputRoles = NN_TRY(convert(outputRoles));
 
-    nn::GeneralResult<nn::SharedBuffer> result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
-                                                 << "uninitialized";
-    auto cb = [&result](ErrorStatus status, const sp<IBuffer>& buffer, uint32_t token) {
-        if (status != ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "IDevice::allocate failed with " << toString(status);
-        } else if (buffer == nullptr) {
-            result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "Returned buffer is nullptr";
-        } else if (token == 0) {
-            result = NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "Returned token is invalid (0)";
-        } else {
-            result = convert(
-                    Buffer::create(buffer, static_cast<nn::Request::MemoryDomainToken>(token)));
-        }
-    };
+    auto cb = hal::utils::CallbackValue(allocationCallback);
 
     const auto ret =
             kDevice->allocate(hidlDesc, hidlPreparedModels, hidlInputRoles, hidlOutputRoles, cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 }  // namespace android::hardware::neuralnetworks::V1_3::utils
diff --git a/neuralnetworks/1.3/utils/src/PreparedModel.cpp b/neuralnetworks/1.3/utils/src/PreparedModel.cpp
index 0bae95d..7b4b7ba 100644
--- a/neuralnetworks/1.3/utils/src/PreparedModel.cpp
+++ b/neuralnetworks/1.3/utils/src/PreparedModel.cpp
@@ -45,25 +45,17 @@
 namespace android::hardware::neuralnetworks::V1_3::utils {
 namespace {
 
-nn::GeneralResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
-convertExecutionResultsHelper(const hidl_vec<V1_2::OutputShape>& outputShapes,
-                              const V1_2::Timing& timing) {
-    return std::make_pair(NN_TRY(nn::convert(outputShapes)), NN_TRY(nn::convert(timing)));
-}
-
-nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> convertExecutionResults(
-        const hidl_vec<V1_2::OutputShape>& outputShapes, const V1_2::Timing& timing) {
-    return hal::utils::makeExecutionFailure(convertExecutionResultsHelper(outputShapes, timing));
-}
-
 nn::GeneralResult<std::pair<nn::Timing, nn::Timing>> convertFencedExecutionCallbackResults(
-        const V1_2::Timing& timingLaunched, const V1_2::Timing& timingFenced) {
+        ErrorStatus status, const V1_2::Timing& timingLaunched, const V1_2::Timing& timingFenced) {
+    HANDLE_HAL_STATUS(status) << "fenced execution callback info failed with " << toString(status);
     return std::make_pair(NN_TRY(nn::convert(timingLaunched)), NN_TRY(nn::convert(timingFenced)));
 }
 
-nn::GeneralResult<std::pair<nn::SyncFence, nn::ExecuteFencedInfoCallback>>
-convertExecuteFencedResults(const hidl_handle& syncFence,
-                            const sp<IFencedExecutionCallback>& callback) {
+nn::GeneralResult<std::pair<nn::SyncFence, nn::ExecuteFencedInfoCallback>> fencedExecutionCallback(
+        ErrorStatus status, const hidl_handle& syncFence,
+        const sp<IFencedExecutionCallback>& callback) {
+    HANDLE_HAL_STATUS(status) << "fenced execution failed with " << toString(status);
+
     auto resultSyncFence = nn::SyncFence::createAsSignaled();
     if (syncFence.getNativeHandle() != nullptr) {
         auto sharedHandle = NN_TRY(nn::convert(syncFence));
@@ -78,23 +70,12 @@
     // Create callback which can be used to retrieve the execution error status and timings.
     nn::ExecuteFencedInfoCallback resultCallback =
             [callback]() -> nn::GeneralResult<std::pair<nn::Timing, nn::Timing>> {
-        nn::GeneralResult<std::pair<nn::Timing, nn::Timing>> result =
-                NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "uninitialized";
-        auto cb = [&result](ErrorStatus status, const V1_2::Timing& timingLaunched,
-                            const V1_2::Timing& timingFenced) {
-            if (status != ErrorStatus::NONE) {
-                const auto canonical =
-                        nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-                result = NN_ERROR(canonical) << "getExecutionInfo failed with " << toString(status);
-            } else {
-                result = convertFencedExecutionCallbackResults(timingLaunched, timingFenced);
-            }
-        };
+        auto cb = hal::utils::CallbackValue(convertFencedExecutionCallbackResults);
 
         const auto ret = callback->getExecutionInfo(cb);
         HANDLE_TRANSPORT_FAILURE(ret);
 
-        return result;
+        return cb.take();
     };
 
     return std::make_pair(std::move(resultSyncFence), std::move(resultCallback));
@@ -103,42 +84,34 @@
 }  // namespace
 
 nn::GeneralResult<std::shared_ptr<const PreparedModel>> PreparedModel::create(
-        sp<V1_3::IPreparedModel> preparedModel) {
+        sp<V1_3::IPreparedModel> preparedModel, bool executeSynchronously) {
     if (preparedModel == nullptr) {
-        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
-               << "V1_3::utils::PreparedModel::create must have non-null preparedModel";
+        return NN_ERROR() << "V1_3::utils::PreparedModel::create must have non-null preparedModel";
     }
 
     auto deathHandler = NN_TRY(hal::utils::DeathHandler::create(preparedModel));
-    return std::make_shared<const PreparedModel>(PrivateConstructorTag{}, std::move(preparedModel),
-                                                 std::move(deathHandler));
+    return std::make_shared<const PreparedModel>(PrivateConstructorTag{}, executeSynchronously,
+                                                 std::move(preparedModel), std::move(deathHandler));
 }
 
-PreparedModel::PreparedModel(PrivateConstructorTag /*tag*/, sp<V1_3::IPreparedModel> preparedModel,
+PreparedModel::PreparedModel(PrivateConstructorTag /*tag*/, bool executeSynchronously,
+                             sp<V1_3::IPreparedModel> preparedModel,
                              hal::utils::DeathHandler deathHandler)
-    : kPreparedModel(std::move(preparedModel)), kDeathHandler(std::move(deathHandler)) {}
+    : kExecuteSynchronously(executeSynchronously),
+      kPreparedModel(std::move(preparedModel)),
+      kDeathHandler(std::move(deathHandler)) {}
 
 nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
 PreparedModel::executeSynchronously(const Request& request, V1_2::MeasureTiming measure,
                                     const OptionalTimePoint& deadline,
                                     const OptionalTimeoutDuration& loopTimeoutDuration) const {
-    nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> result =
-            NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "uninitialized";
-    const auto cb = [&result](ErrorStatus status, const hidl_vec<V1_2::OutputShape>& outputShapes,
-                              const V1_2::Timing& timing) {
-        if (status != ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "executeSynchronously failed with " << toString(status);
-        } else {
-            result = convertExecutionResults(outputShapes, timing);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(executionCallback);
 
     const auto ret = kPreparedModel->executeSynchronously_1_3(request, measure, deadline,
                                                               loopTimeoutDuration, cb);
     HANDLE_TRANSPORT_FAILURE(ret);
 
-    return result;
+    return cb.take();
 }
 
 nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
@@ -151,9 +124,8 @@
     const auto ret =
             kPreparedModel->execute_1_3(request, measure, deadline, loopTimeoutDuration, cb);
     const auto status = HANDLE_TRANSPORT_FAILURE(ret);
-    if (status != ErrorStatus::NONE) {
-        const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-        return NN_ERROR(canonical) << "executeAsynchronously failed with " << toString(status);
+    if (status != ErrorStatus::OUTPUT_INSUFFICIENT_SIZE) {
+        HANDLE_HAL_STATUS(status) << "execution failed with " << toString(status);
     }
 
     return cb->get();
@@ -169,35 +141,22 @@
             hal::utils::flushDataFromPointerToShared(&request, &maybeRequestInShared)));
 
     const auto hidlRequest = NN_TRY(hal::utils::makeExecutionFailure(convert(requestInShared)));
-    const auto hidlMeasure =
-            NN_TRY(hal::utils::makeExecutionFailure(V1_2::utils::convert(measure)));
+    const auto hidlMeasure = NN_TRY(hal::utils::makeExecutionFailure(convert(measure)));
     const auto hidlDeadline = NN_TRY(hal::utils::makeExecutionFailure(convert(deadline)));
     const auto hidlLoopTimeoutDuration =
             NN_TRY(hal::utils::makeExecutionFailure(convert(loopTimeoutDuration)));
 
-    nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> result =
-            NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "uninitialized";
-    const bool preferSynchronous = true;
+    auto result = kExecuteSynchronously
+                          ? executeSynchronously(hidlRequest, hidlMeasure, hidlDeadline,
+                                                 hidlLoopTimeoutDuration)
+                          : executeAsynchronously(hidlRequest, hidlMeasure, hidlDeadline,
+                                                  hidlLoopTimeoutDuration);
+    auto [outputShapes, timing] = NN_TRY(std::move(result));
 
-    // Execute synchronously if allowed.
-    if (preferSynchronous) {
-        result = executeSynchronously(hidlRequest, hidlMeasure, hidlDeadline,
-                                      hidlLoopTimeoutDuration);
-    }
+    NN_TRY(hal::utils::makeExecutionFailure(
+            hal::utils::unflushDataFromSharedToPointer(request, maybeRequestInShared)));
 
-    // Run asymchronous execution if execution has not already completed.
-    if (!result.has_value()) {
-        result = executeAsynchronously(hidlRequest, hidlMeasure, hidlDeadline,
-                                       hidlLoopTimeoutDuration);
-    }
-
-    // Flush output buffers if suxcessful execution.
-    if (result.has_value()) {
-        NN_TRY(hal::utils::makeExecutionFailure(
-                hal::utils::unflushDataFromSharedToPointer(request, maybeRequestInShared)));
-    }
-
-    return result;
+    return std::make_pair(std::move(outputShapes), timing);
 }
 
 nn::GeneralResult<std::pair<nn::SyncFence, nn::ExecuteFencedInfoCallback>>
@@ -212,28 +171,18 @@
 
     const auto hidlRequest = NN_TRY(convert(requestInShared));
     const auto hidlWaitFor = NN_TRY(hal::utils::convertSyncFences(waitFor));
-    const auto hidlMeasure = NN_TRY(V1_2::utils::convert(measure));
+    const auto hidlMeasure = NN_TRY(convert(measure));
     const auto hidlDeadline = NN_TRY(convert(deadline));
     const auto hidlLoopTimeoutDuration = NN_TRY(convert(loopTimeoutDuration));
     const auto hidlTimeoutDurationAfterFence = NN_TRY(convert(timeoutDurationAfterFence));
 
-    nn::GeneralResult<std::pair<nn::SyncFence, nn::ExecuteFencedInfoCallback>> result =
-            NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "uninitialized";
-    auto cb = [&result](ErrorStatus status, const hidl_handle& syncFence,
-                        const sp<IFencedExecutionCallback>& callback) {
-        if (status != ErrorStatus::NONE) {
-            const auto canonical = nn::convert(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
-            result = NN_ERROR(canonical) << "executeFenced failed with " << toString(status);
-        } else {
-            result = convertExecuteFencedResults(syncFence, callback);
-        }
-    };
+    auto cb = hal::utils::CallbackValue(fencedExecutionCallback);
 
     const auto ret = kPreparedModel->executeFenced(hidlRequest, hidlWaitFor, hidlMeasure,
                                                    hidlDeadline, hidlLoopTimeoutDuration,
                                                    hidlTimeoutDurationAfterFence, cb);
     HANDLE_TRANSPORT_FAILURE(ret);
-    auto [syncFence, callback] = NN_TRY(std::move(result));
+    auto [syncFence, callback] = NN_TRY(cb.take());
 
     // If executeFenced required the request memory to be moved into shared memory, block here until
     // the fenced execution has completed and flush the memory back.
diff --git a/neuralnetworks/utils/common/include/nnapi/hal/CommonUtils.h b/neuralnetworks/utils/common/include/nnapi/hal/CommonUtils.h
index 43bb0c6..b3989e5 100644
--- a/neuralnetworks/utils/common/include/nnapi/hal/CommonUtils.h
+++ b/neuralnetworks/utils/common/include/nnapi/hal/CommonUtils.h
@@ -44,9 +44,18 @@
 bool hasNoPointerData(const nn::Model& model);
 bool hasNoPointerData(const nn::Request& request);
 
-// Relocate pointer-based data to shared memory.
+// Relocate pointer-based data to shared memory. If `model` has no Operand::LifeTime::POINTER data,
+// the function returns with a reference to `model`. If `model` has Operand::LifeTime::POINTER data,
+// the model is copied to `maybeModelInSharedOut` with the POINTER data relocated to a memory pool,
+// and the function returns with a reference to `*maybeModelInSharedOut`.
 nn::GeneralResult<std::reference_wrapper<const nn::Model>> flushDataFromPointerToShared(
         const nn::Model* model, std::optional<nn::Model>* maybeModelInSharedOut);
+
+// Relocate pointer-based data to shared memory. If `request` has no
+// Request::Argument::LifeTime::POINTER data, the function returns with a reference to `request`. If
+// `request` has Request::Argument::LifeTime::POINTER data, the request is copied to
+// `maybeRequestInSharedOut` with the POINTER data relocated to a memory pool, and the function
+// returns with a reference to `*maybeRequestInSharedOut`.
 nn::GeneralResult<std::reference_wrapper<const nn::Request>> flushDataFromPointerToShared(
         const nn::Request* request, std::optional<nn::Request>* maybeRequestInSharedOut);
 
diff --git a/neuralnetworks/utils/common/include/nnapi/hal/HandleError.h b/neuralnetworks/utils/common/include/nnapi/hal/HandleError.h
index 78b2a12..95a20a8 100644
--- a/neuralnetworks/utils/common/include/nnapi/hal/HandleError.h
+++ b/neuralnetworks/utils/common/include/nnapi/hal/HandleError.h
@@ -79,4 +79,11 @@
     return makeExecutionFailure(makeGeneralFailure(result, status));
 }
 
+#define HANDLE_HAL_STATUS(status)                                       \
+    if (const auto canonical = ::android::nn::convert(status).value_or( \
+                ::android::nn::ErrorStatus::GENERAL_FAILURE);           \
+        canonical == ::android::nn::ErrorStatus::NONE) {                \
+    } else                                                              \
+        return NN_ERROR(canonical)
+
 }  // namespace android::hardware::neuralnetworks::utils
\ No newline at end of file
diff --git a/neuralnetworks/utils/common/include/nnapi/hal/ResilientBuffer.h b/neuralnetworks/utils/common/include/nnapi/hal/ResilientBuffer.h
index 996ec1e..9d5e3e6 100644
--- a/neuralnetworks/utils/common/include/nnapi/hal/ResilientBuffer.h
+++ b/neuralnetworks/utils/common/include/nnapi/hal/ResilientBuffer.h
@@ -34,7 +34,7 @@
     struct PrivateConstructorTag {};
 
   public:
-    using Factory = std::function<nn::GeneralResult<nn::SharedBuffer>(bool blocking)>;
+    using Factory = std::function<nn::GeneralResult<nn::SharedBuffer>()>;
 
     static nn::GeneralResult<std::shared_ptr<const ResilientBuffer>> create(Factory makeBuffer);
 
diff --git a/neuralnetworks/utils/common/include/nnapi/hal/ResilientDevice.h b/neuralnetworks/utils/common/include/nnapi/hal/ResilientDevice.h
index 4bfed6c..84ae799 100644
--- a/neuralnetworks/utils/common/include/nnapi/hal/ResilientDevice.h
+++ b/neuralnetworks/utils/common/include/nnapi/hal/ResilientDevice.h
@@ -46,8 +46,8 @@
                              nn::Capabilities capabilities, nn::SharedDevice device);
 
     nn::SharedDevice getDevice() const EXCLUDES(mMutex);
-    nn::SharedDevice recover(const nn::IDevice* failingDevice, bool blocking) const
-            EXCLUDES(mMutex);
+    nn::GeneralResult<nn::SharedDevice> recover(const nn::IDevice* failingDevice,
+                                                bool blocking) const EXCLUDES(mMutex);
 
     const std::string& getName() const override;
     const std::string& getVersionString() const override;
@@ -81,17 +81,14 @@
   private:
     bool isValidInternal() const EXCLUDES(mMutex);
     nn::GeneralResult<nn::SharedPreparedModel> prepareModelInternal(
-            bool blocking, const nn::Model& model, nn::ExecutionPreference preference,
-            nn::Priority priority, nn::OptionalTimePoint deadline,
-            const std::vector<nn::SharedHandle>& modelCache,
+            const nn::Model& model, nn::ExecutionPreference preference, nn::Priority priority,
+            nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
             const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const;
     nn::GeneralResult<nn::SharedPreparedModel> prepareModelFromCacheInternal(
-            bool blocking, nn::OptionalTimePoint deadline,
-            const std::vector<nn::SharedHandle>& modelCache,
+            nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
             const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const;
     nn::GeneralResult<nn::SharedBuffer> allocateInternal(
-            bool blocking, const nn::BufferDesc& desc,
-            const std::vector<nn::SharedPreparedModel>& preparedModels,
+            const nn::BufferDesc& desc, const std::vector<nn::SharedPreparedModel>& preparedModels,
             const std::vector<nn::BufferRole>& inputRoles,
             const std::vector<nn::BufferRole>& outputRoles) const;
 
diff --git a/neuralnetworks/utils/common/include/nnapi/hal/ResilientPreparedModel.h b/neuralnetworks/utils/common/include/nnapi/hal/ResilientPreparedModel.h
index d86c88b..faae673 100644
--- a/neuralnetworks/utils/common/include/nnapi/hal/ResilientPreparedModel.h
+++ b/neuralnetworks/utils/common/include/nnapi/hal/ResilientPreparedModel.h
@@ -34,7 +34,7 @@
     struct PrivateConstructorTag {};
 
   public:
-    using Factory = std::function<nn::GeneralResult<nn::SharedPreparedModel>(bool blocking)>;
+    using Factory = std::function<nn::GeneralResult<nn::SharedPreparedModel>()>;
 
     static nn::GeneralResult<std::shared_ptr<const ResilientPreparedModel>> create(
             Factory makePreparedModel);
diff --git a/neuralnetworks/utils/common/include/nnapi/hal/TransferValue.h b/neuralnetworks/utils/common/include/nnapi/hal/TransferValue.h
index 7103c6b..6679afe 100644
--- a/neuralnetworks/utils/common/include/nnapi/hal/TransferValue.h
+++ b/neuralnetworks/utils/common/include/nnapi/hal/TransferValue.h
@@ -17,19 +17,60 @@
 #ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_UTILS_TRANSFER_VALUE_H
 #define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_UTILS_TRANSFER_VALUE_H
 
+#include <android-base/logging.h>
 #include <android-base/thread_annotations.h>
 
 #include <condition_variable>
+#include <functional>
 #include <mutex>
 #include <optional>
+#include <type_traits>
 
 namespace android::hardware::neuralnetworks::utils {
 
-// This class is thread safe.
+// This class adapts a function pointer and offers two affordances:
+// 1) This class object can be used to generate a callback (via the implicit conversion operator)
+//    that can be used to send the result to `CallbackValue` when called.
+// 2) This class object can be used to retrieve the result of the callback with `take`.
+//
+// This class is thread compatible.
+template <typename ReturnType, typename... ArgTypes>
+class CallbackValue final {
+  public:
+    using FunctionType = std::add_pointer_t<ReturnType(ArgTypes...)>;
+    using CallbackType = std::function<void(ArgTypes...)>;
+
+    explicit CallbackValue(FunctionType fn);
+
+    // Creates a callback that forwards its arguments to `mFunction` and stores the result in
+    // `mReturnValue`.
+    /*implicit*/ operator CallbackType();  // NOLINT(google-explicit-constructor)
+
+    // Take the result of calling `mFunction`.
+    // Precondition: mReturnValue.has_value()
+    // Postcondition: !mReturnValue.has_value()
+    [[nodiscard]] ReturnType take();
+
+  private:
+    std::optional<ReturnType> mReturnValue;
+    FunctionType mFunction;
+};
+
+// Deduction guidelines for CallbackValue when constructed with a function pointer.
+template <typename ReturnType, typename... ArgTypes>
+CallbackValue(ReturnType (*)(ArgTypes...))->CallbackValue<ReturnType, ArgTypes...>;
+
+// Thread-safe container to pass a value between threads.
 template <typename Type>
 class TransferValue final {
   public:
+    // Put the value in `TransferValue`. If `TransferValue` already has a value, this function is a
+    // no-op.
     void put(Type object) const;
+
+    // Take the value stored in `TransferValue`. If no value is available, this function will block
+    // until the value becomes available.
+    // Postcondition: !mObject.has_value()
     [[nodiscard]] Type take() const;
 
   private:
@@ -38,7 +79,23 @@
     mutable std::optional<Type> mObject GUARDED_BY(mMutex);
 };
 
-// template implementation
+// template implementations
+
+template <typename ReturnType, typename... ArgTypes>
+CallbackValue<ReturnType, ArgTypes...>::CallbackValue(FunctionType fn) : mFunction(fn) {}
+
+template <typename ReturnType, typename... ArgTypes>
+CallbackValue<ReturnType, ArgTypes...>::operator CallbackType() {
+    return [this](ArgTypes... args) { mReturnValue = mFunction(args...); };
+}
+
+template <typename ReturnType, typename... ArgTypes>
+ReturnType CallbackValue<ReturnType, ArgTypes...>::take() {
+    CHECK(mReturnValue.has_value());
+    std::optional<ReturnType> object;
+    std::swap(object, mReturnValue);
+    return std::move(object).value();
+}
 
 template <typename Type>
 void TransferValue<Type>::put(Type object) const {
@@ -56,6 +113,7 @@
     std::unique_lock lock(mMutex);
     base::ScopedLockAssertion lockAssertion(mMutex);
     mCondition.wait(lock, [this]() REQUIRES(mMutex) { return mObject.has_value(); });
+    CHECK(mObject.has_value());
     std::optional<Type> object;
     std::swap(object, mObject);
     return std::move(object).value();
diff --git a/neuralnetworks/utils/common/src/ResilientBuffer.cpp b/neuralnetworks/utils/common/src/ResilientBuffer.cpp
index 984295b..cf5496a 100644
--- a/neuralnetworks/utils/common/src/ResilientBuffer.cpp
+++ b/neuralnetworks/utils/common/src/ResilientBuffer.cpp
@@ -36,7 +36,7 @@
         return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
                << "utils::ResilientBuffer::create must have non-empty makeBuffer";
     }
-    auto buffer = NN_TRY(makeBuffer(/*blocking=*/true));
+    auto buffer = NN_TRY(makeBuffer());
     CHECK(buffer != nullptr);
     return std::make_shared<const ResilientBuffer>(PrivateConstructorTag{}, std::move(makeBuffer),
                                                    std::move(buffer));
diff --git a/neuralnetworks/utils/common/src/ResilientDevice.cpp b/neuralnetworks/utils/common/src/ResilientDevice.cpp
index 2f83c5c..6ad3fad 100644
--- a/neuralnetworks/utils/common/src/ResilientDevice.cpp
+++ b/neuralnetworks/utils/common/src/ResilientDevice.cpp
@@ -49,7 +49,17 @@
         return result;
     }
 
-    device = resilientDevice.recover(device.get(), blocking);
+    // Attempt recovery and return if it fails.
+    auto maybeDevice = resilientDevice.recover(device.get(), blocking);
+    if (!maybeDevice.has_value()) {
+        const auto& [resultErrorMessage, resultErrorCode] = result.error();
+        const auto& [recoveryErrorMessage, recoveryErrorCode] = maybeDevice.error();
+        return nn::error(resultErrorCode)
+               << resultErrorMessage << ", and failed to recover dead device with error "
+               << recoveryErrorCode << ": " << recoveryErrorMessage;
+    }
+    device = std::move(maybeDevice).value();
+
     return fn(*device);
 }
 
@@ -94,7 +104,8 @@
     return mDevice;
 }
 
-nn::SharedDevice ResilientDevice::recover(const nn::IDevice* failingDevice, bool blocking) const {
+nn::GeneralResult<nn::SharedDevice> ResilientDevice::recover(const nn::IDevice* failingDevice,
+                                                             bool blocking) const {
     std::lock_guard guard(mMutex);
 
     // Another caller updated the failing device.
@@ -102,13 +113,7 @@
         return mDevice;
     }
 
-    auto maybeDevice = kMakeDevice(blocking);
-    if (!maybeDevice.has_value()) {
-        const auto& [message, code] = maybeDevice.error();
-        LOG(ERROR) << "Failed to recover dead device with error " << code << ": " << message;
-        return mDevice;
-    }
-    auto device = std::move(maybeDevice).value();
+    auto device = NN_TRY(kMakeDevice(blocking));
 
     // If recovered device has different metadata than what is cached (i.e., because it was
     // updated), mark the device as invalid and preserve the cached data.
@@ -176,11 +181,11 @@
         nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
         const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const {
     auto self = shared_from_this();
-    ResilientPreparedModel::Factory makePreparedModel =
-            [device = std::move(self), model, preference, priority, deadline, modelCache, dataCache,
-             token](bool blocking) -> nn::GeneralResult<nn::SharedPreparedModel> {
-        return device->prepareModelInternal(blocking, model, preference, priority, deadline,
-                                            modelCache, dataCache, token);
+    ResilientPreparedModel::Factory makePreparedModel = [device = std::move(self), model,
+                                                         preference, priority, deadline, modelCache,
+                                                         dataCache, token] {
+        return device->prepareModelInternal(model, preference, priority, deadline, modelCache,
+                                            dataCache, token);
     };
     return ResilientPreparedModel::create(std::move(makePreparedModel));
 }
@@ -189,11 +194,9 @@
         nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
         const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const {
     auto self = shared_from_this();
-    ResilientPreparedModel::Factory makePreparedModel =
-            [device = std::move(self), deadline, modelCache, dataCache,
-             token](bool blocking) -> nn::GeneralResult<nn::SharedPreparedModel> {
-        return device->prepareModelFromCacheInternal(blocking, deadline, modelCache, dataCache,
-                                                     token);
+    ResilientPreparedModel::Factory makePreparedModel = [device = std::move(self), deadline,
+                                                         modelCache, dataCache, token] {
+        return device->prepareModelFromCacheInternal(deadline, modelCache, dataCache, token);
     };
     return ResilientPreparedModel::create(std::move(makePreparedModel));
 }
@@ -203,10 +206,9 @@
         const std::vector<nn::BufferRole>& inputRoles,
         const std::vector<nn::BufferRole>& outputRoles) const {
     auto self = shared_from_this();
-    ResilientBuffer::Factory makeBuffer =
-            [device = std::move(self), desc, preparedModels, inputRoles,
-             outputRoles](bool blocking) -> nn::GeneralResult<nn::SharedBuffer> {
-        return device->allocateInternal(blocking, desc, preparedModels, inputRoles, outputRoles);
+    ResilientBuffer::Factory makeBuffer = [device = std::move(self), desc, preparedModels,
+                                           inputRoles, outputRoles] {
+        return device->allocateInternal(desc, preparedModels, inputRoles, outputRoles);
     };
     return ResilientBuffer::create(std::move(makeBuffer));
 }
@@ -217,9 +219,8 @@
 }
 
 nn::GeneralResult<nn::SharedPreparedModel> ResilientDevice::prepareModelInternal(
-        bool blocking, const nn::Model& model, nn::ExecutionPreference preference,
-        nn::Priority priority, nn::OptionalTimePoint deadline,
-        const std::vector<nn::SharedHandle>& modelCache,
+        const nn::Model& model, nn::ExecutionPreference preference, nn::Priority priority,
+        nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
         const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const {
     if (!isValidInternal()) {
         return std::make_shared<const InvalidPreparedModel>();
@@ -229,12 +230,11 @@
         return device.prepareModel(model, preference, priority, deadline, modelCache, dataCache,
                                    token);
     };
-    return protect(*this, fn, blocking);
+    return protect(*this, fn, /*blocking=*/false);
 }
 
 nn::GeneralResult<nn::SharedPreparedModel> ResilientDevice::prepareModelFromCacheInternal(
-        bool blocking, nn::OptionalTimePoint deadline,
-        const std::vector<nn::SharedHandle>& modelCache,
+        nn::OptionalTimePoint deadline, const std::vector<nn::SharedHandle>& modelCache,
         const std::vector<nn::SharedHandle>& dataCache, const nn::CacheToken& token) const {
     if (!isValidInternal()) {
         return std::make_shared<const InvalidPreparedModel>();
@@ -242,12 +242,11 @@
     const auto fn = [deadline, &modelCache, &dataCache, token](const nn::IDevice& device) {
         return device.prepareModelFromCache(deadline, modelCache, dataCache, token);
     };
-    return protect(*this, fn, blocking);
+    return protect(*this, fn, /*blocking=*/false);
 }
 
 nn::GeneralResult<nn::SharedBuffer> ResilientDevice::allocateInternal(
-        bool blocking, const nn::BufferDesc& desc,
-        const std::vector<nn::SharedPreparedModel>& preparedModels,
+        const nn::BufferDesc& desc, const std::vector<nn::SharedPreparedModel>& preparedModels,
         const std::vector<nn::BufferRole>& inputRoles,
         const std::vector<nn::BufferRole>& outputRoles) const {
     if (!isValidInternal()) {
@@ -256,7 +255,7 @@
     const auto fn = [&desc, &preparedModels, &inputRoles, &outputRoles](const nn::IDevice& device) {
         return device.allocate(desc, preparedModels, inputRoles, outputRoles);
     };
-    return protect(*this, fn, blocking);
+    return protect(*this, fn, /*blocking=*/false);
 }
 
 }  // namespace android::hardware::neuralnetworks::utils
diff --git a/neuralnetworks/utils/common/src/ResilientPreparedModel.cpp b/neuralnetworks/utils/common/src/ResilientPreparedModel.cpp
index 012a1de..b8acee1 100644
--- a/neuralnetworks/utils/common/src/ResilientPreparedModel.cpp
+++ b/neuralnetworks/utils/common/src/ResilientPreparedModel.cpp
@@ -36,7 +36,7 @@
         return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
                << "utils::ResilientPreparedModel::create must have non-empty makePreparedModel";
     }
-    auto preparedModel = NN_TRY(makePreparedModel(/*blocking=*/true));
+    auto preparedModel = NN_TRY(makePreparedModel());
     CHECK(preparedModel != nullptr);
     return std::make_shared<ResilientPreparedModel>(
             PrivateConstructorTag{}, std::move(makePreparedModel), std::move(preparedModel));
diff --git a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyDerivationFunction.aidl b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyDerivationFunction.aidl
deleted file mode 100644
index 83b7e6e..0000000
--- a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyDerivationFunction.aidl
+++ /dev/null
@@ -1,27 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
-///////////////////////////////////////////////////////////////////////////////
-
-// This file is a snapshot of an AIDL interface (or parcelable). Do not try to
-// edit this file. It looks like you are doing that because you have modified
-// an AIDL interface in a backward-incompatible way, e.g., deleting a function
-// from an interface or a field from a parcelable and it broke the build. That
-// breakage is intended.
-//
-// You must not make a backward incompatible changes to the AIDL files built
-// with the aidl_interface module type with versions property set. The module
-// type is used to build AIDL files in a way that they can be used across
-// independently updatable components of the system. If a device is shipped
-// with such a backward incompatible change, it has a high risk of breaking
-// later when a module using the interface is updated, e.g., Mainline modules.
-
-package android.hardware.security.keymint;
-@Backing(type="int") @VintfStability
-enum KeyDerivationFunction {
-  NONE = 0,
-  RFC5869_SHA256 = 1,
-  ISO18033_2_KDF1_SHA1 = 2,
-  ISO18033_2_KDF1_SHA256 = 3,
-  ISO18033_2_KDF2_SHA1 = 4,
-  ISO18033_2_KDF2_SHA256 = 5,
-}
diff --git a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyParameter.aidl b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyParameter.aidl
index 91f83e4..4985768 100644
--- a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyParameter.aidl
+++ b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyParameter.aidl
@@ -16,11 +16,8 @@
 // later when a module using the interface is updated, e.g., Mainline modules.
 
 package android.hardware.security.keymint;
-@VintfStability
+@RustDerive(Clone=true, Eq=true, Hash=true, Ord=true, PartialEq=true, PartialOrd=true) @VintfStability
 parcelable KeyParameter {
   android.hardware.security.keymint.Tag tag;
-  boolean boolValue;
-  int integer;
-  long longInteger;
-  byte[] blob;
+  android.hardware.security.keymint.KeyParameterValue value;
 }
diff --git a/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyParameterValue.aidl b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyParameterValue.aidl
new file mode 100644
index 0000000..ecf20ad
--- /dev/null
+++ b/security/keymint/aidl/aidl_api/android.hardware.security.keymint/current/android/hardware/security/keymint/KeyParameterValue.aidl
@@ -0,0 +1,36 @@
+///////////////////////////////////////////////////////////////////////////////
+// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
+///////////////////////////////////////////////////////////////////////////////
+
+// This file is a snapshot of an AIDL interface (or parcelable). Do not try to
+// edit this file. It looks like you are doing that because you have modified
+// an AIDL interface in a backward-incompatible way, e.g., deleting a function
+// from an interface or a field from a parcelable and it broke the build. That
+// breakage is intended.
+//
+// You must not make a backward incompatible changes to the AIDL files built
+// with the aidl_interface module type with versions property set. The module
+// type is used to build AIDL files in a way that they can be used across
+// independently updatable components of the system. If a device is shipped
+// with such a backward incompatible change, it has a high risk of breaking
+// later when a module using the interface is updated, e.g., Mainline modules.
+
+package android.hardware.security.keymint;
+@RustDerive(Clone=true, Eq=true, Hash=true, Ord=true, PartialEq=true, PartialOrd=true) @VintfStability
+union KeyParameterValue {
+  int invalid;
+  android.hardware.security.keymint.Algorithm algorithm;
+  android.hardware.security.keymint.BlockMode blockMode;
+  android.hardware.security.keymint.PaddingMode paddingMode;
+  android.hardware.security.keymint.Digest digest;
+  android.hardware.security.keymint.EcCurve ecCurve;
+  android.hardware.security.keymint.KeyOrigin origin;
+  android.hardware.security.keymint.KeyPurpose keyPurpose;
+  android.hardware.security.keymint.HardwareAuthenticatorType hardwareAuthenticatorType;
+  android.hardware.security.keymint.SecurityLevel securityLevel;
+  boolean boolValue;
+  int integer;
+  long longInteger;
+  long dateTime;
+  byte[] blob;
+}
diff --git a/security/keymint/aidl/android/hardware/security/keymint/KeyDerivationFunction.aidl b/security/keymint/aidl/android/hardware/security/keymint/KeyDerivationFunction.aidl
deleted file mode 100644
index e166ab6..0000000
--- a/security/keymint/aidl/android/hardware/security/keymint/KeyDerivationFunction.aidl
+++ /dev/null
@@ -1,37 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package android.hardware.security.keymint;
-
-/**
- * Key derivation functions, mostly used in ECIES.
- */
-@VintfStability
-@Backing(type="int")
-enum KeyDerivationFunction {
-    /** Do not apply a key derivation function; use the raw agreed key */
-    NONE = 0,
-    /** HKDF defined in RFC 5869 with SHA256 */
-    RFC5869_SHA256 = 1,
-    /** KDF1 defined in ISO 18033-2 with SHA1 */
-    ISO18033_2_KDF1_SHA1 = 2,
-    /** KDF1 defined in ISO 18033-2 with SHA256 */
-    ISO18033_2_KDF1_SHA256 = 3,
-    /** KDF2 defined in ISO 18033-2 with SHA1 */
-    ISO18033_2_KDF2_SHA1 = 4,
-    /** KDF2 defined in ISO 18033-2 with SHA256 */
-    ISO18033_2_KDF2_SHA256 = 5,
-}
diff --git a/security/keymint/aidl/android/hardware/security/keymint/KeyParameter.aidl b/security/keymint/aidl/android/hardware/security/keymint/KeyParameter.aidl
index 938064c..f3ed96b 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/KeyParameter.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/KeyParameter.aidl
@@ -16,40 +16,16 @@
 
 package android.hardware.security.keymint;
 
-import android.hardware.security.keymint.Algorithm;
-import android.hardware.security.keymint.BlockMode;
-import android.hardware.security.keymint.Digest;
-import android.hardware.security.keymint.EcCurve;
-import android.hardware.security.keymint.HardwareAuthenticatorType;
-import android.hardware.security.keymint.KeyDerivationFunction;
-import android.hardware.security.keymint.KeyOrigin;
-import android.hardware.security.keymint.KeyPurpose;
-import android.hardware.security.keymint.PaddingMode;
-import android.hardware.security.keymint.SecurityLevel;
 import android.hardware.security.keymint.Tag;
-
+import android.hardware.security.keymint.KeyParameterValue;
 
 /**
  * Identifies the key authorization parameters to be used with keyMint.  This is usually
  * provided as an array of KeyParameters to IKeyMintDevice or Operation.
- *
- * TODO(seleneh): Union was not supported in aidl when this cl is first drafted.  So we just had
- * the Tags, and bool, int, long, int[], and we will cast to the appropate types base on the
- * Tag value.  We need to update this defination to distingish Algorithm, BlockMode,
- * PaddingMode, KeyOrigin...etc later, as union support is recently added to aidl.
- * b/173253030
  */
 @VintfStability
+@RustDerive(Clone=true, Eq=true, PartialEq=true, Ord=true, PartialOrd=true, Hash=true)
 parcelable KeyParameter {
-    /**
-     * Identify what type of key parameter this parcelable actually holds, and based on the type
-     * of tag is int, long, bool, or byte[], one of the fields below will be referenced.
-     */
     Tag tag;
-
-    boolean boolValue;
-    int integer;
-    long longInteger;
-    // TODO: change this to nullable.
-    byte[] blob;
+    KeyParameterValue value;
 }
diff --git a/security/keymint/aidl/android/hardware/security/keymint/KeyParameterValue.aidl b/security/keymint/aidl/android/hardware/security/keymint/KeyParameterValue.aidl
new file mode 100644
index 0000000..a4f5154
--- /dev/null
+++ b/security/keymint/aidl/android/hardware/security/keymint/KeyParameterValue.aidl
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.security.keymint;
+
+import android.hardware.security.keymint.Algorithm;
+import android.hardware.security.keymint.BlockMode;
+import android.hardware.security.keymint.Digest;
+import android.hardware.security.keymint.EcCurve;
+import android.hardware.security.keymint.HardwareAuthenticatorType;
+import android.hardware.security.keymint.KeyOrigin;
+import android.hardware.security.keymint.KeyPurpose;
+import android.hardware.security.keymint.PaddingMode;
+import android.hardware.security.keymint.SecurityLevel;
+
+@VintfStability
+@RustDerive(Clone=true, Eq=true, PartialEq=true, Ord=true, PartialOrd=true, Hash=true)
+union KeyParameterValue {
+
+    /* Represents an invalid value type. */
+    int invalid;
+
+    /* Enum types */
+    Algorithm algorithm;
+    BlockMode blockMode;
+    PaddingMode paddingMode;
+    Digest digest;
+    EcCurve ecCurve;
+    KeyOrigin origin;
+    KeyPurpose keyPurpose;
+    HardwareAuthenticatorType hardwareAuthenticatorType;
+    SecurityLevel securityLevel;
+
+    /* Other types */
+    boolean boolValue;  // Always true, if present.
+    int integer;
+    long longInteger;
+    long dateTime;
+
+    byte[] blob;
+}
diff --git a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
index 9ba4099..94bc199 100644
--- a/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintAidlTestBase.cpp
@@ -577,8 +577,8 @@
     string ciphertext = EncryptMessage(message, params, &out_params);
     EXPECT_EQ(1U, out_params.size());
     auto ivVal = out_params.GetTagValue(TAG_NONCE);
-    EXPECT_TRUE(ivVal.isOk());
-    if (ivVal.isOk()) *iv_out = ivVal.value();
+    EXPECT_TRUE(ivVal);
+    if (ivVal) *iv_out = *ivVal;
     return ciphertext;
 }
 
diff --git a/security/keymint/aidl/vts/functional/KeyMintTest.cpp b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
index 6e38539..3060153 100644
--- a/security/keymint/aidl/vts/functional/KeyMintTest.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
@@ -80,7 +80,10 @@
 template <TagType tag_type, Tag tag, typename ValueT>
 bool contains(vector<KeyParameter>& set, TypedTag<tag_type, tag> ttag, ValueT expected_value) {
     auto it = std::find_if(set.begin(), set.end(), [&](const KeyParameter& param) {
-        return param.tag == tag && accessTagValue(ttag, param) == expected_value;
+        if (auto p = authorizationValue(ttag, param)) {
+            return *p == expected_value;
+        }
+        return false;
     });
     return (it != set.end());
 }
@@ -251,10 +254,10 @@
 
         EXPECT_TRUE(auths.Contains(TAG_OS_VERSION, os_version()))
                 << "OS version is " << os_version() << " key reported "
-                << auths.GetTagValue(TAG_OS_VERSION);
+                << auths.GetTagValue(TAG_OS_VERSION)->get();
         EXPECT_TRUE(auths.Contains(TAG_OS_PATCHLEVEL, os_patch_level()))
                 << "OS patch level is " << os_patch_level() << " key reported "
-                << auths.GetTagValue(TAG_OS_PATCHLEVEL);
+                << auths.GetTagValue(TAG_OS_PATCHLEVEL)->get();
     }
 };
 
@@ -2333,8 +2336,8 @@
 
 vector<uint8_t> CopyIv(const AuthorizationSet& set) {
     auto iv = set.GetTagValue(TAG_NONCE);
-    EXPECT_TRUE(iv.isOk());
-    return iv.value();
+    EXPECT_TRUE(iv);
+    return iv->get();
 }
 
 /*
@@ -2459,13 +2462,13 @@
                 case BlockMode::CBC:
                 case BlockMode::GCM:
                 case BlockMode::CTR:
-                    ASSERT_TRUE(iv.isOk()) << "No IV for block mode " << block_mode;
-                    EXPECT_EQ(block_mode == BlockMode::GCM ? 12U : 16U, iv.value().size());
-                    params.push_back(TAG_NONCE, iv.value());
+                    ASSERT_TRUE(iv) << "No IV for block mode " << block_mode;
+                    EXPECT_EQ(block_mode == BlockMode::GCM ? 12U : 16U, iv->get().size());
+                    params.push_back(TAG_NONCE, iv->get());
                     break;
 
                 case BlockMode::ECB:
-                    EXPECT_FALSE(iv.isOk()) << "ECB mode should not generate IV";
+                    EXPECT_FALSE(iv) << "ECB mode should not generate IV";
                     break;
             }
 
@@ -2649,9 +2652,9 @@
     AuthorizationSet out_params;
     string ciphertext = EncryptMessage(message, params, &out_params);
     EXPECT_EQ(message.size(), ciphertext.size());
-    EXPECT_EQ(16U, out_params.GetTagValue(TAG_NONCE).value().size());
+    EXPECT_EQ(16U, out_params.GetTagValue(TAG_NONCE)->get().size());
 
-    params.push_back(TAG_NONCE, out_params.GetTagValue(TAG_NONCE).value());
+    params.push_back(TAG_NONCE, out_params.GetTagValue(TAG_NONCE)->get());
     string plaintext = DecryptMessage(ciphertext, params);
     EXPECT_EQ(message, plaintext);
 
@@ -2697,9 +2700,9 @@
     AuthorizationSet out_params;
     string ciphertext = EncryptMessage(message, params, &out_params);
     EXPECT_EQ(message.size(), ciphertext.size());
-    EXPECT_EQ(16U, out_params.GetTagValue(TAG_NONCE).value().size());
+    EXPECT_EQ(16U, out_params.GetTagValue(TAG_NONCE)->get().size());
 
-    params.push_back(TAG_NONCE, out_params.GetTagValue(TAG_NONCE).value());
+    params.push_back(TAG_NONCE, out_params.GetTagValue(TAG_NONCE)->get());
     string plaintext = DecryptMessage(ciphertext, params);
     EXPECT_EQ(message, plaintext);
 
@@ -2893,7 +2896,7 @@
     AuthorizationSet begin_out_params;
     EXPECT_EQ(ErrorCode::OK, Begin(KeyPurpose::ENCRYPT, params, &begin_out_params));
     EXPECT_EQ(1U, begin_out_params.size());
-    ASSERT_TRUE(begin_out_params.GetTagValue(TAG_NONCE).isOk());
+    ASSERT_TRUE(begin_out_params.GetTagValue(TAG_NONCE));
 
     AuthorizationSet finish_out_params;
     string ciphertext;
diff --git a/security/keymint/support/authorization_set.cpp b/security/keymint/support/authorization_set.cpp
index 37b6cd1..f98851c 100644
--- a/security/keymint/support/authorization_set.cpp
+++ b/security/keymint/support/authorization_set.cpp
@@ -106,10 +106,11 @@
     return false;
 }
 
-NullOr<const KeyParameter&> AuthorizationSet::GetEntry(Tag tag) const {
+std::optional<std::reference_wrapper<const KeyParameter>> AuthorizationSet::GetEntry(
+        Tag tag) const {
     int pos = find(tag);
     if (pos == -1) return {};
-    return data_[pos];
+    return std::reference_wrapper(data_[pos]);
 }
 
 AuthorizationSetBuilder& AuthorizationSetBuilder::RsaKey(uint32_t key_size,
diff --git a/security/keymint/support/include/keymint_support/authorization_set.h b/security/keymint/support/include/keymint_support/authorization_set.h
index c85f305..4ff1705 100644
--- a/security/keymint/support/include/keymint_support/authorization_set.h
+++ b/security/keymint/support/include/keymint_support/authorization_set.h
@@ -168,7 +168,7 @@
     bool Contains(TypedTag<tag_type, tag> ttag, const ValueT& value) const {
         for (const auto& param : data_) {
             auto entry = authorizationValue(ttag, param);
-            if (entry.isOk() && static_cast<ValueT>(entry.value()) == value) return true;
+            if (entry && static_cast<ValueT>(*entry) == value) return true;
         }
         return false;
     }
@@ -178,9 +178,9 @@
     size_t GetTagCount(Tag tag) const;
 
     template <typename T>
-    inline NullOr<const typename TypedTag2ValueType<T>::type&> GetTagValue(T tag) const {
+    inline auto GetTagValue(T tag) const -> decltype(authorizationValue(tag, KeyParameter())) {
         auto entry = GetEntry(tag);
-        if (entry.isOk()) return authorizationValue(tag, entry.value());
+        if (entry) return authorizationValue(tag, *entry);
         return {};
     }
 
@@ -219,7 +219,7 @@
     }
 
   private:
-    NullOr<const KeyParameter&> GetEntry(Tag tag) const;
+    std::optional<std::reference_wrapper<const KeyParameter>> GetEntry(Tag tag) const;
 
     std::vector<KeyParameter> data_;
 };
diff --git a/security/keymint/support/include/keymint_support/key_param_output.h b/security/keymint/support/include/keymint_support/key_param_output.h
index 6e0e35d..5f004fe 100644
--- a/security/keymint/support/include/keymint_support/key_param_output.h
+++ b/security/keymint/support/include/keymint_support/key_param_output.h
@@ -71,7 +71,7 @@
 }
 
 template <typename ValueT>
-::std::ostream& operator<<(::std::ostream& os, const NullOr<ValueT>& value) {
+::std::ostream& operator<<(::std::ostream& os, const std::optional<ValueT>& value) {
     if (!value.isOk()) {
         os << "(value not present)";
     } else {
diff --git a/security/keymint/support/include/keymint_support/keymint_tags.h b/security/keymint/support/include/keymint_support/keymint_tags.h
index 4e3d7ff..d932b40 100644
--- a/security/keymint/support/include/keymint_support/keymint_tags.h
+++ b/security/keymint/support/include/keymint_support/keymint_tags.h
@@ -58,6 +58,10 @@
     typedef TypedTag<typeFromTag(tag), tag> type;
 };
 
+#ifdef DECLARE_TYPED_TAG
+#undef DECLARE_TYPED_TAG
+#endif
+
 #define DECLARE_TYPED_TAG(name)                                    \
     typedef typename Tag2TypedTag<Tag::name>::type TAG_##name##_t; \
     static TAG_##name##_t TAG_##name;
@@ -72,9 +76,12 @@
 DECLARE_TYPED_TAG(ATTESTATION_CHALLENGE);
 DECLARE_TYPED_TAG(ATTESTATION_ID_BRAND);
 DECLARE_TYPED_TAG(ATTESTATION_ID_DEVICE);
-DECLARE_TYPED_TAG(ATTESTATION_ID_PRODUCT);
+DECLARE_TYPED_TAG(ATTESTATION_ID_IMEI);
 DECLARE_TYPED_TAG(ATTESTATION_ID_MANUFACTURER);
+DECLARE_TYPED_TAG(ATTESTATION_ID_MEID);
+DECLARE_TYPED_TAG(ATTESTATION_ID_PRODUCT);
 DECLARE_TYPED_TAG(ATTESTATION_ID_MODEL);
+DECLARE_TYPED_TAG(ATTESTATION_ID_SERIAL);
 DECLARE_TYPED_TAG(AUTH_TIMEOUT);
 DECLARE_TYPED_TAG(BLOCK_MODE);
 DECLARE_TYPED_TAG(BOOTLOADER_ONLY);
@@ -118,6 +125,8 @@
 DECLARE_TYPED_TAG(USER_SECURE_ID);
 DECLARE_TYPED_TAG(VENDOR_PATCHLEVEL);
 
+#undef DECLARE_TYPED_TAG
+
 template <typename... Elems>
 struct MetaList {};
 
@@ -133,6 +142,7 @@
         TAG_OS_VERSION_t, TAG_OS_PATCHLEVEL_t, TAG_UNIQUE_ID_t, TAG_ATTESTATION_CHALLENGE_t,
         TAG_ATTESTATION_APPLICATION_ID_t, TAG_ATTESTATION_ID_BRAND_t, TAG_ATTESTATION_ID_DEVICE_t,
         TAG_ATTESTATION_ID_PRODUCT_t, TAG_ATTESTATION_ID_MANUFACTURER_t, TAG_ATTESTATION_ID_MODEL_t,
+        TAG_ATTESTATION_ID_SERIAL_t, TAG_ATTESTATION_ID_IMEI_t, TAG_ATTESTATION_ID_MEID_t,
         TAG_RESET_SINCE_ID_ROTATION_t, TAG_PURPOSE_t, TAG_ALGORITHM_t, TAG_BLOCK_MODE_t,
         TAG_DIGEST_t, TAG_PADDING_t, TAG_ORIGIN_t, TAG_USER_AUTH_TYPE_t, TAG_EC_CURVE_t,
         TAG_BOOT_PATCHLEVEL_t, TAG_VENDOR_PATCHLEVEL_t, TAG_TRUSTED_CONFIRMATION_REQUIRED_t,
@@ -141,72 +151,121 @@
 template <typename TypedTagType>
 struct TypedTag2ValueType;
 
-#define MAKE_TAG_VALUE_ACCESSOR(tag_type, field_name)                              \
-    template <Tag tag>                                                             \
-    struct TypedTag2ValueType<TypedTag<tag_type, tag>> {                           \
-        typedef decltype(static_cast<KeyParameter*>(nullptr)->field_name) type;    \
-    };                                                                             \
-    template <Tag tag>                                                             \
-    inline auto accessTagValue(TypedTag<tag_type, tag>, const KeyParameter& param) \
-            ->const decltype(param.field_name)& {                                  \
-        return param.field_name;                                                   \
-    }                                                                              \
-    template <Tag tag>                                                             \
-    inline auto accessTagValue(TypedTag<tag_type, tag>, KeyParameter& param)       \
-            ->decltype(param.field_name)& {                                        \
-        return param.field_name;                                                   \
+#ifdef MAKE_TAG_VALUE_ACCESSOR
+#undef MAKE_TAG_VALUE_ACCESSOR
+#endif
+
+#define MAKE_TAG_VALUE_ACCESSOR(tag_type, field_name)                                           \
+    template <Tag tag>                                                                          \
+    struct TypedTag2ValueType<TypedTag<tag_type, tag>> {                                        \
+        using type = std::remove_reference<                                                     \
+                decltype(static_cast<KeyParameterValue*>(nullptr)                               \
+                                 ->get<KeyParameterValue::field_name>())>::type;                \
+        static constexpr KeyParameterValue::Tag unionTag = KeyParameterValue::field_name;       \
+    };                                                                                          \
+    template <Tag tag>                                                                          \
+    inline std::optional<std::reference_wrapper<                                                \
+            const typename TypedTag2ValueType<TypedTag<tag_type, tag>>::type>>                  \
+    accessTagValue(TypedTag<tag_type, tag>, const KeyParameter& param) {                        \
+        if (param.value.getTag() == KeyParameterValue::field_name) {                            \
+            return std::optional(                                                               \
+                    std::reference_wrapper(param.value.get<KeyParameterValue::field_name>()));  \
+        } else {                                                                                \
+            return std::nullopt;                                                                \
+        }                                                                                       \
+    }                                                                                           \
+    template <Tag tag>                                                                          \
+    inline std::optional<                                                                       \
+            std::reference_wrapper<typename TypedTag2ValueType<TypedTag<tag_type, tag>>::type>> \
+    accessTagValue(TypedTag<tag_type, tag>, KeyParameter& param) {                              \
+        if (param.value.getTag() == KeyParameterValue::field_name) {                            \
+            return std::optional(                                                               \
+                    std::reference_wrapper(param.value.get<KeyParameterValue::field_name>()));  \
+        } else {                                                                                \
+            return std::nullopt;                                                                \
+        }                                                                                       \
     }
 
 MAKE_TAG_VALUE_ACCESSOR(TagType::ULONG, longInteger)
 MAKE_TAG_VALUE_ACCESSOR(TagType::ULONG_REP, longInteger)
-MAKE_TAG_VALUE_ACCESSOR(TagType::DATE, longInteger)
+MAKE_TAG_VALUE_ACCESSOR(TagType::DATE, dateTime)
 MAKE_TAG_VALUE_ACCESSOR(TagType::UINT, integer)
 MAKE_TAG_VALUE_ACCESSOR(TagType::UINT_REP, integer)
 MAKE_TAG_VALUE_ACCESSOR(TagType::BOOL, boolValue)
 MAKE_TAG_VALUE_ACCESSOR(TagType::BYTES, blob)
 MAKE_TAG_VALUE_ACCESSOR(TagType::BIGNUM, blob)
 
-//  TODO(seleneh) change these MAKE_TAG_ENUM_VALUE_ACCESSOR back to the 2 parameter
-//  version when aidl supports union
-#define MAKE_TAG_ENUM_VALUE_ACCESSOR(typed_tag, field_name, field_type)                 \
-    template <>                                                                         \
-    struct TypedTag2ValueType<decltype(typed_tag)> {                                    \
-        typedef field_type type;                                                        \
-    };                                                                                  \
-    inline auto accessTagValue(decltype(typed_tag), const KeyParameter& param)          \
-            ->const field_type& {                                                       \
-        return *reinterpret_cast<const field_type*>(&param.field_name);                 \
-    }                                                                                   \
-    inline auto accessTagValue(decltype(typed_tag), KeyParameter& param)->field_type& { \
-        return *reinterpret_cast<field_type*>(&param.field_name);                       \
+#undef MAKE_TAG_VALUE_ACCESSOR
+
+#ifdef MAKE_TAG_ENUM_VALUE_ACCESSOR
+#undef MAKE_TAG_ENUM_VALUE_ACCESSOR
+#endif
+
+#define MAKE_TAG_ENUM_VALUE_ACCESSOR(typed_tag, field_name)                                       \
+    template <>                                                                                   \
+    struct TypedTag2ValueType<decltype(typed_tag)> {                                              \
+        using type = std::remove_reference<                                                       \
+                decltype(static_cast<KeyParameterValue*>(nullptr)                                 \
+                                 ->get<KeyParameterValue::field_name>())>::type;                  \
+        static constexpr KeyParameterValue::Tag unionTag = KeyParameterValue::field_name;         \
+    };                                                                                            \
+    inline std::optional<                                                                         \
+            std::reference_wrapper<const typename TypedTag2ValueType<decltype(typed_tag)>::type>> \
+    accessTagValue(decltype(typed_tag), const KeyParameter& param) {                              \
+        if (param.value.getTag() == KeyParameterValue::field_name) {                              \
+            return std::optional(                                                                 \
+                    std::reference_wrapper(param.value.get<KeyParameterValue::field_name>()));    \
+        } else {                                                                                  \
+            return std::nullopt;                                                                  \
+        }                                                                                         \
+    }                                                                                             \
+    inline std::optional<                                                                         \
+            std::reference_wrapper<typename TypedTag2ValueType<decltype(typed_tag)>::type>>       \
+    accessTagValue(decltype(typed_tag), KeyParameter& param) {                                    \
+        if (param.value.getTag() == KeyParameterValue::field_name) {                              \
+            return std::optional(                                                                 \
+                    std::reference_wrapper(param.value.get<KeyParameterValue::field_name>()));    \
+        } else {                                                                                  \
+            return std::nullopt;                                                                  \
+        }                                                                                         \
     }
 
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_ALGORITHM, integer, Algorithm)
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_BLOCK_MODE, integer, BlockMode)
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_DIGEST, integer, Digest)
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_EC_CURVE, integer, EcCurve)
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_ORIGIN, integer, KeyOrigin)
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_PADDING, integer, PaddingMode)
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_PURPOSE, integer, KeyPurpose)
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_USER_AUTH_TYPE, integer, HardwareAuthenticatorType)
-MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_HARDWARE_TYPE, integer, SecurityLevel)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_ALGORITHM, algorithm)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_BLOCK_MODE, blockMode)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_DIGEST, digest)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_EC_CURVE, ecCurve)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_ORIGIN, origin)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_PADDING, paddingMode)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_PURPOSE, keyPurpose)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_USER_AUTH_TYPE, hardwareAuthenticatorType)
+MAKE_TAG_ENUM_VALUE_ACCESSOR(TAG_HARDWARE_TYPE, securityLevel)
+
+#undef MAKE_TAG_ENUM_VALUE_ACCESSOR
 
 template <TagType tag_type, Tag tag, typename ValueT>
 inline KeyParameter makeKeyParameter(TypedTag<tag_type, tag> ttag, ValueT&& value) {
-    KeyParameter param;
-    param.tag = tag;
-    param.longInteger = 0;
-    accessTagValue(ttag, param) = std::forward<ValueT>(value);
-    return param;
+    KeyParameter retval;
+    retval.tag = tag;
+    retval.value = KeyParameterValue::make<TypedTag2ValueType<decltype(ttag)>::unionTag>(
+            std::forward<ValueT>(value));
+    return retval;
 }
 
 // the boolean case
 template <Tag tag>
 inline KeyParameter makeKeyParameter(TypedTag<TagType::BOOL, tag>) {
-    KeyParameter param;
-    param.tag = tag;
-    param.boolValue = true;
-    return param;
+    KeyParameter retval;
+    retval.tag = tag;
+    retval.value = KeyParameterValue::make<KeyParameterValue::boolValue>(true);
+    return retval;
+}
+
+// the invalid case
+inline KeyParameter makeKeyParameter(TypedTag<TagType::INVALID, Tag::INVALID>) {
+    KeyParameter retval;
+    retval.tag = Tag::INVALID;
+    retval.value = KeyParameterValue::make<KeyParameterValue::invalid>(0);
+    return retval;
 }
 
 template <typename... Pack>
@@ -239,89 +298,32 @@
     return makeKeyParameter(ttag, std::forward<Args>(args)...);
 }
 
-/**
- * This class wraps a (mostly return) value and stores whether or not the wrapped value is valid out
- * of band. Note that if the wrapped value is a reference it is unsafe to access the value if
- * !isOk(). If the wrapped type is a pointer or value and !isOk(), it is still safe to access the
- * wrapped value. In this case the pointer will be NULL though, and the value will be default
- * constructed.
- *
- * TODO(seleneh) replace this with std::optional.
- */
-template <typename ValueT>
-class NullOr {
-    using internal_t = std::conditional_t<std::is_lvalue_reference<ValueT>::value,
-                                          std::remove_reference_t<ValueT>*, ValueT>;
-
-    struct pointer_initializer {
-        static std::nullptr_t init() { return nullptr; }
-    };
-    struct value_initializer {
-        static ValueT init() { return ValueT(); }
-    };
-    struct value_pointer_deref_t {
-        static ValueT& deref(ValueT& v) { return v; }
-    };
-    struct reference_deref_t {
-        static auto& deref(internal_t v) { return *v; }
-    };
-    using initializer_t = std::conditional_t<std::is_lvalue_reference<ValueT>::value ||
-                                                     std::is_pointer<ValueT>::value,
-                                             pointer_initializer, value_initializer>;
-    using deref_t = std::conditional_t<std::is_lvalue_reference<ValueT>::value, reference_deref_t,
-                                       value_pointer_deref_t>;
-
-  public:
-    NullOr() : value_(initializer_t::init()), null_(true) {}
-    template <typename T>
-    NullOr(T&& value, typename std::enable_if<
-                              !std::is_lvalue_reference<ValueT>::value &&
-                                      std::is_same<std::decay_t<ValueT>, std::decay_t<T>>::value,
-                              int>::type = 0)
-        : value_(std::forward<ValueT>(value)), null_(false) {}
-    template <typename T>
-    NullOr(T& value, typename std::enable_if<
-                             std::is_lvalue_reference<ValueT>::value &&
-                                     std::is_same<std::decay_t<ValueT>, std::decay_t<T>>::value,
-                             int>::type = 0)
-        : value_(&value), null_(false) {}
-
-    bool isOk() const { return !null_; }
-
-    const ValueT& value() const& { return deref_t::deref(value_); }
-    ValueT& value() & { return deref_t::deref(value_); }
-    ValueT&& value() && { return std::move(deref_t::deref(value_)); }
-
-  private:
-    internal_t value_;
-    bool null_;
-};
-
 template <typename T>
 std::remove_reference_t<T> NullOrOr(T&& v) {
-    if (v.isOk()) return v;
+    if (v) return v;
     return {};
 }
 
 template <typename Head, typename... Tail>
 std::remove_reference_t<Head> NullOrOr(Head&& head, Tail&&... tail) {
-    if (head.isOk()) return head;
+    if (head) return head;
     return NullOrOr(std::forward<Tail>(tail)...);
 }
 
 template <typename Default, typename Wrapped>
-std::remove_reference_t<Wrapped> defaultOr(NullOr<Wrapped>&& optional, Default&& def) {
+std::remove_reference_t<Wrapped> defaultOr(std::optional<Wrapped>&& optional, Default&& def) {
     static_assert(std::is_convertible<std::remove_reference_t<Default>,
                                       std::remove_reference_t<Wrapped>>::value,
-                  "Type of default value must match the type wrapped by NullOr");
-    if (optional.isOk()) return optional.value();
+                  "Type of default value must match the type wrapped by std::optional");
+    if (optional) return *optional;
     return def;
 }
 
 template <TagType tag_type, Tag tag>
-inline NullOr<const typename TypedTag2ValueType<TypedTag<tag_type, tag>>::type&> authorizationValue(
-        TypedTag<tag_type, tag> ttag, const KeyParameter& param) {
-    if (tag != param.tag) return {};
+inline std::optional<
+        std::reference_wrapper<const typename TypedTag2ValueType<TypedTag<tag_type, tag>>::type>>
+authorizationValue(TypedTag<tag_type, tag> ttag, const KeyParameter& param) {
+    if (TypedTag2ValueType<TypedTag<tag_type, tag>>::unionTag != param.value.getTag()) return {};
     return accessTagValue(ttag, param);
 }
 
diff --git a/security/keymint/support/key_param_output.cpp b/security/keymint/support/key_param_output.cpp
index c56e035..0950eb6 100644
--- a/security/keymint/support/key_param_output.cpp
+++ b/security/keymint/support/key_param_output.cpp
@@ -35,38 +35,8 @@
     return os;
 }
 
-// TODO(seleneh) update this to a parsing that looks at each tags individually
-// such as ALGORITHM BLOCK_MODE when aidl union support is added.
 ostream& operator<<(ostream& os, const KeyParameter& param) {
-    os << param.tag << ": ";
-    switch (typeFromTag(param.tag)) {
-        case TagType::INVALID:
-            return os << " Invalid";
-        case TagType::ENUM_REP:
-        case TagType::ENUM:
-        case TagType::UINT_REP:
-        case TagType::UINT:
-            return os << param.integer;
-        case TagType::ULONG_REP:
-        case TagType::ULONG:
-        case TagType::DATE:
-            return os << param.longInteger;
-        case TagType::BOOL:
-            return os << "true";
-        case TagType::BIGNUM:
-            os << " Bignum: ";
-            for (size_t i = 0; i < param.blob.size(); ++i) {
-                os << std::hex << ::std::setw(2) << static_cast<int>(param.blob[i]) << ::std::dec;
-            }
-            return os;
-        case TagType::BYTES:
-            os << " Bytes: ";
-            for (size_t i = 0; i < param.blob.size(); ++i) {
-                os << ::std::hex << ::std::setw(2) << static_cast<int>(param.blob[i]) << ::std::dec;
-            }
-            return os;
-    }
-    return os << "UNKNOWN TAG TYPE!";
+    return os << param.toString();
 }
 
 }  // namespace aidl::android::hardware::security::keymint
diff --git a/wifi/1.5/default/wifi_legacy_hal.cpp b/wifi/1.5/default/wifi_legacy_hal.cpp
index 773dd9b..e1a5a8c 100644
--- a/wifi/1.5/default/wifi_legacy_hal.cpp
+++ b/wifi/1.5/default/wifi_legacy_hal.cpp
@@ -343,6 +343,43 @@
         on_nan_event_schedule_update_user_callback(*event);
     }
 }
+
+// Callbacks for the various TWT operations.
+std::function<void(const TwtSetupResponse&)>
+    on_twt_event_setup_response_callback;
+void onAsyncTwtEventSetupResponse(TwtSetupResponse* event) {
+    const auto lock = hidl_sync_util::acquireGlobalLock();
+    if (on_twt_event_setup_response_callback && event) {
+        on_twt_event_setup_response_callback(*event);
+    }
+}
+
+std::function<void(const TwtTeardownCompletion&)>
+    on_twt_event_teardown_completion_callback;
+void onAsyncTwtEventTeardownCompletion(TwtTeardownCompletion* event) {
+    const auto lock = hidl_sync_util::acquireGlobalLock();
+    if (on_twt_event_teardown_completion_callback && event) {
+        on_twt_event_teardown_completion_callback(*event);
+    }
+}
+
+std::function<void(const TwtInfoFrameReceived&)>
+    on_twt_event_info_frame_received_callback;
+void onAsyncTwtEventInfoFrameReceived(TwtInfoFrameReceived* event) {
+    const auto lock = hidl_sync_util::acquireGlobalLock();
+    if (on_twt_event_info_frame_received_callback && event) {
+        on_twt_event_info_frame_received_callback(*event);
+    }
+}
+
+std::function<void(const TwtDeviceNotify&)> on_twt_event_device_notify_callback;
+void onAsyncTwtEventDeviceNotify(TwtDeviceNotify* event) {
+    const auto lock = hidl_sync_util::acquireGlobalLock();
+    if (on_twt_event_device_notify_callback && event) {
+        on_twt_event_device_notify_callback(*event);
+    }
+}
+
 // End of the free-standing "C" style callbacks.
 
 WifiLegacyHal::WifiLegacyHal(
@@ -1529,6 +1566,70 @@
         restrictions);
 }
 
+wifi_error WifiLegacyHal::setVoipMode(const std::string& iface_name,
+                                      wifi_voip_mode mode) {
+    return global_func_table_.wifi_set_voip_mode(getIfaceHandle(iface_name),
+                                                 mode);
+}
+
+wifi_error WifiLegacyHal::twtRegisterHandler(
+    const std::string& iface_name, const TwtCallbackHandlers& user_callbacks) {
+    on_twt_event_setup_response_callback = user_callbacks.on_setup_response;
+    on_twt_event_teardown_completion_callback =
+        user_callbacks.on_teardown_completion;
+    on_twt_event_info_frame_received_callback =
+        user_callbacks.on_info_frame_received;
+    on_twt_event_device_notify_callback = user_callbacks.on_device_notify;
+
+    return global_func_table_.wifi_twt_register_handler(
+        getIfaceHandle(iface_name),
+        {onAsyncTwtEventSetupResponse, onAsyncTwtEventTeardownCompletion,
+         onAsyncTwtEventInfoFrameReceived, onAsyncTwtEventDeviceNotify});
+}
+
+std::pair<wifi_error, TwtCapabilitySet> WifiLegacyHal::twtGetCapability(
+    const std::string& iface_name) {
+    TwtCapabilitySet capSet;
+    wifi_error status = global_func_table_.wifi_twt_get_capability(
+        getIfaceHandle(iface_name), &capSet);
+    return {status, capSet};
+}
+
+wifi_error WifiLegacyHal::twtSetupRequest(const std::string& iface_name,
+                                          const TwtSetupRequest& msg) {
+    TwtSetupRequest msgInternal(msg);
+    return global_func_table_.wifi_twt_setup_request(getIfaceHandle(iface_name),
+                                                     &msgInternal);
+}
+
+wifi_error WifiLegacyHal::twtTearDownRequest(const std::string& iface_name,
+                                             const TwtTeardownRequest& msg) {
+    TwtTeardownRequest msgInternal(msg);
+    return global_func_table_.wifi_twt_teardown_request(
+        getIfaceHandle(iface_name), &msgInternal);
+}
+
+wifi_error WifiLegacyHal::twtInfoFrameRequest(const std::string& iface_name,
+                                              const TwtInfoFrameRequest& msg) {
+    TwtInfoFrameRequest msgInternal(msg);
+    return global_func_table_.wifi_twt_info_frame_request(
+        getIfaceHandle(iface_name), &msgInternal);
+}
+
+std::pair<wifi_error, TwtStats> WifiLegacyHal::twtGetStats(
+    const std::string& iface_name, uint8_t configId) {
+    TwtStats stats;
+    wifi_error status = global_func_table_.wifi_twt_get_stats(
+        getIfaceHandle(iface_name), configId, &stats);
+    return {status, stats};
+}
+
+wifi_error WifiLegacyHal::twtClearStats(const std::string& iface_name,
+                                        uint8_t configId) {
+    return global_func_table_.wifi_twt_clear_stats(getIfaceHandle(iface_name),
+                                                   configId);
+}
+
 void WifiLegacyHal::invalidate() {
     global_handle_ = nullptr;
     iface_name_to_handle_.clear();
@@ -1560,6 +1661,10 @@
     on_nan_event_range_request_user_callback = nullptr;
     on_nan_event_range_report_user_callback = nullptr;
     on_nan_event_schedule_update_user_callback = nullptr;
+    on_twt_event_setup_response_callback = nullptr;
+    on_twt_event_teardown_completion_callback = nullptr;
+    on_twt_event_info_frame_received_callback = nullptr;
+    on_twt_event_device_notify_callback = nullptr;
 }
 
 }  // namespace legacy_hal
diff --git a/wifi/1.5/default/wifi_legacy_hal.h b/wifi/1.5/default/wifi_legacy_hal.h
index 6266cf6..11efe7e 100644
--- a/wifi/1.5/default/wifi_legacy_hal.h
+++ b/wifi/1.5/default/wifi_legacy_hal.h
@@ -164,6 +164,18 @@
 using on_radio_mode_change_callback =
     std::function<void(const std::vector<WifiMacInfo>&)>;
 
+// TWT response and event callbacks struct.
+struct TwtCallbackHandlers {
+    // Callback for TWT setup response
+    std::function<void(const TwtSetupResponse&)> on_setup_response;
+    // Callback for TWT teardown completion
+    std::function<void(const TwtTeardownCompletion&)> on_teardown_completion;
+    // Callback for TWT info frame received event
+    std::function<void(const TwtInfoFrameReceived&)> on_info_frame_received;
+    // Callback for TWT notification from the device
+    std::function<void(const TwtDeviceNotify&)> on_device_notify;
+};
+
 /**
  * Class that encapsulates all legacy HAL interactions.
  * This class manages the lifetime of the event loop thread used by legacy HAL.
@@ -391,6 +403,28 @@
         std::vector<wifi_coex_unsafe_channel> unsafe_channels,
         uint32_t restrictions);
 
+    wifi_error setVoipMode(const std::string& iface_name, wifi_voip_mode mode);
+
+    wifi_error twtRegisterHandler(const std::string& iface_name,
+                                  const TwtCallbackHandlers& handler);
+
+    std::pair<wifi_error, TwtCapabilitySet> twtGetCapability(
+        const std::string& iface_name);
+
+    wifi_error twtSetupRequest(const std::string& iface_name,
+                               const TwtSetupRequest& msg);
+
+    wifi_error twtTearDownRequest(const std::string& iface_name,
+                                  const TwtTeardownRequest& msg);
+
+    wifi_error twtInfoFrameRequest(const std::string& iface_name,
+                                   const TwtInfoFrameRequest& msg);
+
+    std::pair<wifi_error, TwtStats> twtGetStats(const std::string& iface_name,
+                                                uint8_t configId);
+
+    wifi_error twtClearStats(const std::string& iface_name, uint8_t configId);
+
    private:
     // Retrieve interface handles for all the available interfaces.
     wifi_error retrieveIfaceHandles();
diff --git a/wifi/1.5/default/wifi_legacy_hal_stubs.cpp b/wifi/1.5/default/wifi_legacy_hal_stubs.cpp
index b6c908b..4b005d6 100644
--- a/wifi/1.5/default/wifi_legacy_hal_stubs.cpp
+++ b/wifi/1.5/default/wifi_legacy_hal_stubs.cpp
@@ -150,7 +150,14 @@
     populateStubFor(&hal_fn->wifi_multi_sta_set_primary_connection);
     populateStubFor(&hal_fn->wifi_multi_sta_set_use_case);
     populateStubFor(&hal_fn->wifi_set_coex_unsafe_channels);
-
+    populateStubFor(&hal_fn->wifi_set_voip_mode);
+    populateStubFor(&hal_fn->wifi_twt_register_handler);
+    populateStubFor(&hal_fn->wifi_twt_get_capability);
+    populateStubFor(&hal_fn->wifi_twt_setup_request);
+    populateStubFor(&hal_fn->wifi_twt_teardown_request);
+    populateStubFor(&hal_fn->wifi_twt_info_frame_request);
+    populateStubFor(&hal_fn->wifi_twt_get_stats);
+    populateStubFor(&hal_fn->wifi_twt_clear_stats);
     return true;
 }
 }  // namespace legacy_hal