diff --git a/neuralnetworks/1.2/utils/Android.bp b/neuralnetworks/1.2/utils/Android.bp
index a1dd3d0..22e8659 100644
--- a/neuralnetworks/1.2/utils/Android.bp
+++ b/neuralnetworks/1.2/utils/Android.bp
@@ -20,6 +20,7 @@
     srcs: ["src/*"],
     local_include_dirs: ["include/nnapi/hal/1.2/"],
     export_include_dirs: ["include"],
+    cflags: ["-Wthread-safety"],
     static_libs: [
         "neuralnetworks_types",
         "neuralnetworks_utils_hal_common",
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
new file mode 100644
index 0000000..bc7d92a
--- /dev/null
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Callbacks.h
@@ -0,0 +1,76 @@
+/*
+ * 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.
+ */
+
+#ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_CALLBACKS_H
+#define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_CALLBACKS_H
+
+#include <android/hardware/neuralnetworks/1.0/IExecutionCallback.h>
+#include <android/hardware/neuralnetworks/1.0/IPreparedModelCallback.h>
+#include <android/hardware/neuralnetworks/1.0/types.h>
+#include <android/hardware/neuralnetworks/1.2/IExecutionCallback.h>
+#include <android/hardware/neuralnetworks/1.2/IPreparedModelCallback.h>
+#include <android/hardware/neuralnetworks/1.2/types.h>
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/1.0/Callbacks.h>
+#include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/ProtectCallback.h>
+#include <nnapi/hal/TransferValue.h>
+
+namespace android::hardware::neuralnetworks::V1_2::utils {
+
+class PreparedModelCallback final : public IPreparedModelCallback,
+                                    public hal::utils::IProtectedCallback {
+  public:
+    using Data = nn::GeneralResult<nn::SharedPreparedModel>;
+
+    Return<void> notify(V1_0::ErrorStatus status,
+                        const sp<V1_0::IPreparedModel>& preparedModel) override;
+    Return<void> notify_1_2(V1_0::ErrorStatus status,
+                            const sp<IPreparedModel>& preparedModel) override;
+
+    void notifyAsDeadObject() override;
+
+    Data get();
+
+  private:
+    void notifyInternal(Data result);
+
+    hal::utils::TransferValue<Data> mData;
+};
+
+class ExecutionCallback final : public IExecutionCallback, public hal::utils::IProtectedCallback {
+  public:
+    using Data = nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>;
+
+    Return<void> notify(V1_0::ErrorStatus status) override;
+    Return<void> notify_1_2(V1_0::ErrorStatus status, const hidl_vec<OutputShape>& outputShapes,
+                            const Timing& timing) override;
+
+    void notifyAsDeadObject() override;
+
+    Data get();
+
+  private:
+    void notifyInternal(Data result);
+
+    hal::utils::TransferValue<Data> mData;
+};
+
+}  // namespace android::hardware::neuralnetworks::V1_2::utils
+
+#endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_CALLBACKS_H
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 81bf792..e6de011 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
@@ -24,62 +24,64 @@
 
 namespace android::nn {
 
-Result<OperandType> convert(const hal::V1_2::OperandType& operandType);
-Result<OperationType> convert(const hal::V1_2::OperationType& operationType);
-Result<DeviceType> convert(const hal::V1_2::DeviceType& deviceType);
-Result<Capabilities> convert(const hal::V1_2::Capabilities& capabilities);
-Result<Capabilities::OperandPerformance> convert(
+GeneralResult<OperandType> convert(const hal::V1_2::OperandType& operandType);
+GeneralResult<OperationType> convert(const hal::V1_2::OperationType& operationType);
+GeneralResult<DeviceType> convert(const hal::V1_2::DeviceType& deviceType);
+GeneralResult<Capabilities> convert(const hal::V1_2::Capabilities& capabilities);
+GeneralResult<Capabilities::OperandPerformance> convert(
         const hal::V1_2::Capabilities::OperandPerformance& operandPerformance);
-Result<Operation> convert(const hal::V1_2::Operation& operation);
-Result<Operand::SymmPerChannelQuantParams> convert(
+GeneralResult<Operation> convert(const hal::V1_2::Operation& operation);
+GeneralResult<Operand::SymmPerChannelQuantParams> convert(
         const hal::V1_2::SymmPerChannelQuantParams& symmPerChannelQuantParams);
-Result<Operand> convert(const hal::V1_2::Operand& operand);
-Result<Operand::ExtraParams> convert(const hal::V1_2::Operand::ExtraParams& extraParams);
-Result<Model> convert(const hal::V1_2::Model& model);
-Result<Model::ExtensionNameAndPrefix> convert(
+GeneralResult<Operand> convert(const hal::V1_2::Operand& operand);
+GeneralResult<Operand::ExtraParams> convert(const hal::V1_2::Operand::ExtraParams& extraParams);
+GeneralResult<Model> convert(const hal::V1_2::Model& model);
+GeneralResult<Model::ExtensionNameAndPrefix> convert(
         const hal::V1_2::Model::ExtensionNameAndPrefix& extensionNameAndPrefix);
-Result<OutputShape> convert(const hal::V1_2::OutputShape& outputShape);
-Result<MeasureTiming> convert(const hal::V1_2::MeasureTiming& measureTiming);
-Result<Timing> convert(const hal::V1_2::Timing& timing);
-Result<Extension> convert(const hal::V1_2::Extension& extension);
-Result<Extension::OperandTypeInformation> convert(
+GeneralResult<OutputShape> convert(const hal::V1_2::OutputShape& outputShape);
+GeneralResult<MeasureTiming> convert(const hal::V1_2::MeasureTiming& measureTiming);
+GeneralResult<Timing> convert(const hal::V1_2::Timing& timing);
+GeneralResult<Extension> convert(const hal::V1_2::Extension& extension);
+GeneralResult<Extension::OperandTypeInformation> convert(
         const hal::V1_2::Extension::OperandTypeInformation& operandTypeInformation);
-Result<NativeHandle> convert(const hardware::hidl_handle& handle);
+GeneralResult<NativeHandle> convert(const hardware::hidl_handle& handle);
 
-Result<std::vector<Extension>> convert(const hardware::hidl_vec<hal::V1_2::Extension>& extensions);
-Result<std::vector<NativeHandle>> convert(const hardware::hidl_vec<hardware::hidl_handle>& handles);
-Result<std::vector<OutputShape>> convert(
+GeneralResult<std::vector<Extension>> convert(
+        const hardware::hidl_vec<hal::V1_2::Extension>& extensions);
+GeneralResult<std::vector<NativeHandle>> convert(
+        const hardware::hidl_vec<hardware::hidl_handle>& handles);
+GeneralResult<std::vector<OutputShape>> convert(
         const hardware::hidl_vec<hal::V1_2::OutputShape>& outputShapes);
 
 }  // namespace android::nn
 
 namespace android::hardware::neuralnetworks::V1_2::utils {
 
-nn::Result<OperandType> convert(const nn::OperandType& operandType);
-nn::Result<OperationType> convert(const nn::OperationType& operationType);
-nn::Result<DeviceType> convert(const nn::DeviceType& deviceType);
-nn::Result<Capabilities> convert(const nn::Capabilities& capabilities);
-nn::Result<Capabilities::OperandPerformance> convert(
+nn::GeneralResult<OperandType> convert(const nn::OperandType& operandType);
+nn::GeneralResult<OperationType> convert(const nn::OperationType& operationType);
+nn::GeneralResult<DeviceType> convert(const nn::DeviceType& deviceType);
+nn::GeneralResult<Capabilities> convert(const nn::Capabilities& capabilities);
+nn::GeneralResult<Capabilities::OperandPerformance> convert(
         const nn::Capabilities::OperandPerformance& operandPerformance);
-nn::Result<Operation> convert(const nn::Operation& operation);
-nn::Result<SymmPerChannelQuantParams> convert(
+nn::GeneralResult<Operation> convert(const nn::Operation& operation);
+nn::GeneralResult<SymmPerChannelQuantParams> convert(
         const nn::Operand::SymmPerChannelQuantParams& symmPerChannelQuantParams);
-nn::Result<Operand> convert(const nn::Operand& operand);
-nn::Result<Operand::ExtraParams> convert(const nn::Operand::ExtraParams& extraParams);
-nn::Result<Model> convert(const nn::Model& model);
-nn::Result<Model::ExtensionNameAndPrefix> convert(
+nn::GeneralResult<Operand> convert(const nn::Operand& operand);
+nn::GeneralResult<Operand::ExtraParams> convert(const nn::Operand::ExtraParams& extraParams);
+nn::GeneralResult<Model> convert(const nn::Model& model);
+nn::GeneralResult<Model::ExtensionNameAndPrefix> convert(
         const nn::Model::ExtensionNameAndPrefix& extensionNameAndPrefix);
-nn::Result<OutputShape> convert(const nn::OutputShape& outputShape);
-nn::Result<MeasureTiming> convert(const nn::MeasureTiming& measureTiming);
-nn::Result<Timing> convert(const nn::Timing& timing);
-nn::Result<Extension> convert(const nn::Extension& extension);
-nn::Result<Extension::OperandTypeInformation> convert(
+nn::GeneralResult<OutputShape> convert(const nn::OutputShape& outputShape);
+nn::GeneralResult<MeasureTiming> convert(const nn::MeasureTiming& measureTiming);
+nn::GeneralResult<Timing> convert(const nn::Timing& timing);
+nn::GeneralResult<Extension> convert(const nn::Extension& extension);
+nn::GeneralResult<Extension::OperandTypeInformation> convert(
         const nn::Extension::OperandTypeInformation& operandTypeInformation);
-nn::Result<hidl_handle> convert(const nn::NativeHandle& handle);
+nn::GeneralResult<hidl_handle> convert(const nn::NativeHandle& handle);
 
-nn::Result<hidl_vec<Extension>> convert(const std::vector<nn::Extension>& extensions);
-nn::Result<hidl_vec<hidl_handle>> convert(const std::vector<nn::NativeHandle>& handles);
-nn::Result<hidl_vec<OutputShape>> convert(const std::vector<nn::OutputShape>& outputShapes);
+nn::GeneralResult<hidl_vec<Extension>> convert(const std::vector<nn::Extension>& extensions);
+nn::GeneralResult<hidl_vec<hidl_handle>> convert(const std::vector<nn::NativeHandle>& handles);
+nn::GeneralResult<hidl_vec<OutputShape>> convert(const std::vector<nn::OutputShape>& outputShapes);
 
 }  // namespace android::hardware::neuralnetworks::V1_2::utils
 
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
new file mode 100644
index 0000000..eb317b1
--- /dev/null
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Device.h
@@ -0,0 +1,98 @@
+/*
+ * 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.
+ */
+
+#ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_DEVICE_H
+#define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_DEVICE_H
+
+#include <android/hardware/neuralnetworks/1.2/IDevice.h>
+#include <nnapi/IBuffer.h>
+#include <nnapi/IDevice.h>
+#include <nnapi/OperandTypes.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/ProtectCallback.h>
+
+#include <functional>
+#include <memory>
+#include <optional>
+#include <string>
+#include <vector>
+
+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<nn::Capabilities> initCapabilities(V1_2::IDevice* device);
+nn::GeneralResult<std::pair<uint32_t, uint32_t>> initNumberOfCacheFilesNeeded(
+        V1_2::IDevice* device);
+
+class Device final : public nn::IDevice {
+    struct PrivateConstructorTag {};
+
+  public:
+    static nn::GeneralResult<std::shared_ptr<const Device>> create(std::string name,
+                                                                   sp<V1_2::IDevice> device);
+
+    Device(PrivateConstructorTag tag, std::string name, std::string versionString,
+           nn::DeviceType deviceType, std::vector<nn::Extension> extensions,
+           nn::Capabilities capabilities, std::pair<uint32_t, uint32_t> numberOfCacheFilesNeeded,
+           sp<V1_2::IDevice> device, hal::utils::DeathHandler deathHandler);
+
+    const std::string& getName() const override;
+    const std::string& getVersionString() const override;
+    nn::Version getFeatureLevel() const override;
+    nn::DeviceType getType() const override;
+    const std::vector<nn::Extension>& getSupportedExtensions() const override;
+    const nn::Capabilities& getCapabilities() const override;
+    std::pair<uint32_t, uint32_t> getNumberOfCacheFilesNeeded() const override;
+
+    nn::GeneralResult<void> wait() const override;
+
+    nn::GeneralResult<std::vector<bool>> getSupportedOperations(
+            const nn::Model& model) const override;
+
+    nn::GeneralResult<nn::SharedPreparedModel> prepareModel(
+            const nn::Model& model, nn::ExecutionPreference preference, nn::Priority priority,
+            nn::OptionalTimePoint deadline, const std::vector<nn::NativeHandle>& modelCache,
+            const std::vector<nn::NativeHandle>& dataCache,
+            const nn::CacheToken& token) const override;
+
+    nn::GeneralResult<nn::SharedPreparedModel> prepareModelFromCache(
+            nn::OptionalTimePoint deadline, const std::vector<nn::NativeHandle>& modelCache,
+            const std::vector<nn::NativeHandle>& dataCache,
+            const nn::CacheToken& token) const override;
+
+    nn::GeneralResult<nn::SharedBuffer> allocate(
+            const nn::BufferDesc& desc, const std::vector<nn::SharedPreparedModel>& preparedModels,
+            const std::vector<nn::BufferRole>& inputRoles,
+            const std::vector<nn::BufferRole>& outputRoles) const override;
+
+  private:
+    const std::string kName;
+    const std::string kVersionString;
+    const nn::DeviceType kDeviceType;
+    const std::vector<nn::Extension> kExtensions;
+    const nn::Capabilities kCapabilities;
+    const std::pair<uint32_t, uint32_t> kNumberOfCacheFilesNeeded;
+    const sp<V1_2::IDevice> kDevice;
+    const hal::utils::DeathHandler kDeathHandler;
+};
+
+}  // namespace android::hardware::neuralnetworks::V1_2::utils
+
+#endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_DEVICE_H
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
new file mode 100644
index 0000000..65e1e8a
--- /dev/null
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/PreparedModel.h
@@ -0,0 +1,70 @@
+/*
+ * 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.
+ */
+
+#ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_PREPARED_MODEL_H
+#define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_PREPARED_MODEL_H
+
+#include <android/hardware/neuralnetworks/1.2/IPreparedModel.h>
+#include <android/hardware/neuralnetworks/1.2/types.h>
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/ProtectCallback.h>
+
+#include <memory>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+namespace android::hardware::neuralnetworks::V1_2::utils {
+
+class PreparedModel final : public nn::IPreparedModel {
+    struct PrivateConstructorTag {};
+
+  public:
+    static nn::GeneralResult<std::shared_ptr<const PreparedModel>> create(
+            sp<V1_2::IPreparedModel> preparedModel);
+
+    PreparedModel(PrivateConstructorTag tag, 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,
+            const nn::OptionalTimePoint& deadline,
+            const nn::OptionalTimeoutDuration& loopTimeoutDuration) const override;
+
+    nn::GeneralResult<std::pair<nn::SyncFence, nn::ExecuteFencedInfoCallback>> executeFenced(
+            const nn::Request& request, const std::vector<nn::SyncFence>& waitFor,
+            nn::MeasureTiming measure, const nn::OptionalTimePoint& deadline,
+            const nn::OptionalTimeoutDuration& loopTimeoutDuration,
+            const nn::OptionalTimeoutDuration& timeoutDurationAfterFence) const override;
+
+    std::any getUnderlyingResource() const override;
+
+  private:
+    nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executeSynchronously(
+            const V1_0::Request& request, MeasureTiming measure) const;
+    nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> executeAsynchronously(
+            const V1_0::Request& request, MeasureTiming measure) const;
+
+    const sp<V1_2::IPreparedModel> kPreparedModel;
+    const hal::utils::DeathHandler kDeathHandler;
+};
+
+}  // namespace android::hardware::neuralnetworks::V1_2::utils
+
+#endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_PREPARED_MODEL_H
diff --git a/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Service.h b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Service.h
new file mode 100644
index 0000000..44f004f
--- /dev/null
+++ b/neuralnetworks/1.2/utils/include/nnapi/hal/1.2/Service.h
@@ -0,0 +1,31 @@
+/*
+ * 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.
+ */
+
+#ifndef ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_SERVICE_H
+#define ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_SERVICE_H
+
+#include <nnapi/IDevice.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <string>
+
+namespace android::hardware::neuralnetworks::V1_2::utils {
+
+nn::GeneralResult<nn::SharedDevice> getDevice(const std::string& name);
+
+}  // namespace android::hardware::neuralnetworks::V1_2::utils
+
+#endif  // ANDROID_HARDWARE_INTERFACES_NEURALNETWORKS_1_2_UTILS_SERVICE_H
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 b1c2f1a..a9a6bae 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
@@ -22,6 +22,7 @@
 #include <android-base/logging.h>
 #include <android/hardware/neuralnetworks/1.2/types.h>
 #include <nnapi/Result.h>
+#include <nnapi/TypeUtils.h>
 #include <nnapi/Types.h>
 #include <nnapi/Validation.h>
 #include <nnapi/hal/1.0/Conversions.h>
@@ -38,10 +39,14 @@
 
 template <typename Type>
 nn::Result<void> validate(const Type& halObject) {
-    const auto canonical = NN_TRY(nn::convert(halObject));
-    const auto version = NN_TRY(nn::validate(canonical));
+    const auto maybeCanonical = nn::convert(halObject);
+    if (!maybeCanonical.has_value()) {
+        return nn::error() << maybeCanonical.error().message;
+    }
+    const auto version = NN_TRY(nn::validate(maybeCanonical.value()));
     if (version > utils::kVersion) {
-        return NN_ERROR() << "";
+        return NN_ERROR() << "Insufficient version: " << version << " vs required "
+                          << utils::kVersion;
     }
     return {};
 }
@@ -58,9 +63,14 @@
 template <typename Type>
 decltype(nn::convert(std::declval<Type>())) validatedConvertToCanonical(const Type& halObject) {
     auto canonical = NN_TRY(nn::convert(halObject));
-    const auto version = NN_TRY(nn::validate(canonical));
+    const auto maybeVersion = nn::validate(canonical);
+    if (!maybeVersion.has_value()) {
+        return nn::error() << maybeVersion.error();
+    }
+    const auto version = maybeVersion.value();
     if (version > utils::kVersion) {
-        return NN_ERROR() << "";
+        return NN_ERROR() << "Insufficient version: " << version << " vs required "
+                          << utils::kVersion;
     }
     return canonical;
 }
diff --git a/neuralnetworks/1.2/utils/src/Callbacks.cpp b/neuralnetworks/1.2/utils/src/Callbacks.cpp
new file mode 100644
index 0000000..cb739f0
--- /dev/null
+++ b/neuralnetworks/1.2/utils/src/Callbacks.cpp
@@ -0,0 +1,147 @@
+/*
+ * 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 "Callbacks.h"
+
+#include "Conversions.h"
+#include "PreparedModel.h"
+#include "Utils.h"
+
+#include <android/hardware/neuralnetworks/1.0/types.h>
+#include <android/hardware/neuralnetworks/1.2/IExecutionCallback.h>
+#include <android/hardware/neuralnetworks/1.2/IPreparedModelCallback.h>
+#include <android/hardware/neuralnetworks/1.2/types.h>
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/1.0/Conversions.h>
+#include <nnapi/hal/1.0/PreparedModel.h>
+#include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/HandleError.h>
+#include <nnapi/hal/ProtectCallback.h>
+#include <nnapi/hal/TransferValue.h>
+
+#include <utility>
+
+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(validatedConvertToCanonical(outputShapes)),
+                          NN_TRY(validatedConvertToCanonical(timing)));
+}
+
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
+convertExecutionGeneralResults(const hidl_vec<OutputShape>& outputShapes, const Timing& timing) {
+    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 =
+                validatedConvertToCanonical(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));
+    }
+    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 =
+                validatedConvertToCanonical(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));
+    }
+    return Void();
+}
+
+void PreparedModelCallback::notifyAsDeadObject() {
+    notifyInternal(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 =
+                validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+        notifyInternal(NN_ERROR(canonical) << "execute failed with " << toString(status));
+    } else {
+        notifyInternal({});
+    }
+    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 =
+                validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+        notifyInternal(NN_ERROR(canonical) << "execute failed with " << toString(status));
+    } else {
+        notifyInternal(convertExecutionGeneralResults(outputShapes, timing));
+    }
+    return Void();
+}
+
+void ExecutionCallback::notifyAsDeadObject() {
+    notifyInternal(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 fed314b..378719a 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/hal/1.0/Conversions.h>
 #include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/HandleError.h>
 
 #include <algorithm>
 #include <functional>
@@ -78,7 +79,7 @@
 using ConvertOutput = std::decay_t<decltype(convert(std::declval<Input>()).value())>;
 
 template <typename Type>
-Result<std::vector<ConvertOutput<Type>>> convertVec(const hidl_vec<Type>& arguments) {
+GeneralResult<std::vector<ConvertOutput<Type>>> convertVec(const hidl_vec<Type>& arguments) {
     std::vector<ConvertOutput<Type>> canonical;
     canonical.reserve(arguments.size());
     for (const auto& argument : arguments) {
@@ -88,25 +89,25 @@
 }
 
 template <typename Type>
-Result<std::vector<ConvertOutput<Type>>> convert(const hidl_vec<Type>& arguments) {
+GeneralResult<std::vector<ConvertOutput<Type>>> convert(const hidl_vec<Type>& arguments) {
     return convertVec(arguments);
 }
 
 }  // anonymous namespace
 
-Result<OperandType> convert(const hal::V1_2::OperandType& operandType) {
+GeneralResult<OperandType> convert(const hal::V1_2::OperandType& operandType) {
     return static_cast<OperandType>(operandType);
 }
 
-Result<OperationType> convert(const hal::V1_2::OperationType& operationType) {
+GeneralResult<OperationType> convert(const hal::V1_2::OperationType& operationType) {
     return static_cast<OperationType>(operationType);
 }
 
-Result<DeviceType> convert(const hal::V1_2::DeviceType& deviceType) {
+GeneralResult<DeviceType> convert(const hal::V1_2::DeviceType& deviceType) {
     return static_cast<DeviceType>(deviceType);
 }
 
-Result<Capabilities> convert(const hal::V1_2::Capabilities& capabilities) {
+GeneralResult<Capabilities> convert(const hal::V1_2::Capabilities& capabilities) {
     const bool validOperandTypes = std::all_of(
             capabilities.operandPerformance.begin(), capabilities.operandPerformance.end(),
             [](const hal::V1_2::Capabilities::OperandPerformance& operandPerformance) {
@@ -114,7 +115,7 @@
                 return !maybeType.has_value() ? false : validOperandType(maybeType.value());
             });
     if (!validOperandTypes) {
-        return NN_ERROR()
+        return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
                << "Invalid OperandType when converting OperandPerformance in Capabilities";
     }
 
@@ -124,8 +125,9 @@
             NN_TRY(convert(capabilities.relaxedFloat32toFloat16PerformanceTensor));
     auto operandPerformance = NN_TRY(convert(capabilities.operandPerformance));
 
-    auto table =
-            NN_TRY(Capabilities::OperandPerformanceTable::create(std::move(operandPerformance)));
+    auto table = NN_TRY(hal::utils::makeGeneralFailure(
+            Capabilities::OperandPerformanceTable::create(std::move(operandPerformance)),
+            nn::ErrorStatus::GENERAL_FAILURE));
 
     return Capabilities{
             .relaxedFloat32toFloat16PerformanceScalar = relaxedFloat32toFloat16PerformanceScalar,
@@ -134,7 +136,7 @@
     };
 }
 
-Result<Capabilities::OperandPerformance> convert(
+GeneralResult<Capabilities::OperandPerformance> convert(
         const hal::V1_2::Capabilities::OperandPerformance& operandPerformance) {
     return Capabilities::OperandPerformance{
             .type = NN_TRY(convert(operandPerformance.type)),
@@ -142,7 +144,7 @@
     };
 }
 
-Result<Operation> convert(const hal::V1_2::Operation& operation) {
+GeneralResult<Operation> convert(const hal::V1_2::Operation& operation) {
     return Operation{
             .type = NN_TRY(convert(operation.type)),
             .inputs = operation.inputs,
@@ -150,7 +152,7 @@
     };
 }
 
-Result<Operand::SymmPerChannelQuantParams> convert(
+GeneralResult<Operand::SymmPerChannelQuantParams> convert(
         const hal::V1_2::SymmPerChannelQuantParams& symmPerChannelQuantParams) {
     return Operand::SymmPerChannelQuantParams{
             .scales = symmPerChannelQuantParams.scales,
@@ -158,7 +160,7 @@
     };
 }
 
-Result<Operand> convert(const hal::V1_2::Operand& operand) {
+GeneralResult<Operand> convert(const hal::V1_2::Operand& operand) {
     return Operand{
             .type = NN_TRY(convert(operand.type)),
             .dimensions = operand.dimensions,
@@ -170,7 +172,7 @@
     };
 }
 
-Result<Operand::ExtraParams> convert(const hal::V1_2::Operand::ExtraParams& extraParams) {
+GeneralResult<Operand::ExtraParams> convert(const hal::V1_2::Operand::ExtraParams& extraParams) {
     using Discriminator = hal::V1_2::Operand::ExtraParams::hidl_discriminator;
     switch (extraParams.getDiscriminator()) {
         case Discriminator::none:
@@ -180,11 +182,12 @@
         case Discriminator::extension:
             return extraParams.extension();
     }
-    return NN_ERROR() << "Unrecognized Operand::ExtraParams discriminator: "
-                      << underlyingType(extraParams.getDiscriminator());
+    return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
+           << "Unrecognized Operand::ExtraParams discriminator: "
+           << underlyingType(extraParams.getDiscriminator());
 }
 
-Result<Model> convert(const hal::V1_2::Model& model) {
+GeneralResult<Model> convert(const hal::V1_2::Model& model) {
     auto operations = NN_TRY(convert(model.operations));
 
     // Verify number of consumers.
@@ -193,9 +196,9 @@
     CHECK(model.operands.size() == numberOfConsumers.size());
     for (size_t i = 0; i < model.operands.size(); ++i) {
         if (model.operands[i].numberOfConsumers != numberOfConsumers[i]) {
-            return NN_ERROR() << "Invalid numberOfConsumers for operand " << i << ", expected "
-                              << numberOfConsumers[i] << " but found "
-                              << model.operands[i].numberOfConsumers;
+            return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
+                   << "Invalid numberOfConsumers for operand " << i << ", expected "
+                   << numberOfConsumers[i] << " but found " << model.operands[i].numberOfConsumers;
         }
     }
 
@@ -215,7 +218,7 @@
     };
 }
 
-Result<Model::ExtensionNameAndPrefix> convert(
+GeneralResult<Model::ExtensionNameAndPrefix> convert(
         const hal::V1_2::Model::ExtensionNameAndPrefix& extensionNameAndPrefix) {
     return Model::ExtensionNameAndPrefix{
             .name = extensionNameAndPrefix.name,
@@ -223,29 +226,29 @@
     };
 }
 
-Result<OutputShape> convert(const hal::V1_2::OutputShape& outputShape) {
+GeneralResult<OutputShape> convert(const hal::V1_2::OutputShape& outputShape) {
     return OutputShape{
             .dimensions = outputShape.dimensions,
             .isSufficient = outputShape.isSufficient,
     };
 }
 
-Result<MeasureTiming> convert(const hal::V1_2::MeasureTiming& measureTiming) {
+GeneralResult<MeasureTiming> convert(const hal::V1_2::MeasureTiming& measureTiming) {
     return static_cast<MeasureTiming>(measureTiming);
 }
 
-Result<Timing> convert(const hal::V1_2::Timing& timing) {
+GeneralResult<Timing> convert(const hal::V1_2::Timing& timing) {
     return Timing{.timeOnDevice = timing.timeOnDevice, .timeInDriver = timing.timeInDriver};
 }
 
-Result<Extension> convert(const hal::V1_2::Extension& extension) {
+GeneralResult<Extension> convert(const hal::V1_2::Extension& extension) {
     return Extension{
             .name = extension.name,
             .operandTypes = NN_TRY(convert(extension.operandTypes)),
     };
 }
 
-Result<Extension::OperandTypeInformation> convert(
+GeneralResult<Extension::OperandTypeInformation> convert(
         const hal::V1_2::Extension::OperandTypeInformation& operandTypeInformation) {
     return Extension::OperandTypeInformation{
             .type = operandTypeInformation.type,
@@ -254,20 +257,21 @@
     };
 }
 
-Result<NativeHandle> convert(const hidl_handle& handle) {
+GeneralResult<NativeHandle> convert(const hidl_handle& handle) {
     auto* cloned = native_handle_clone(handle.getNativeHandle());
     return ::android::NativeHandle::create(cloned, /*ownsHandle=*/true);
 }
 
-Result<std::vector<Extension>> convert(const hidl_vec<hal::V1_2::Extension>& extensions) {
+GeneralResult<std::vector<Extension>> convert(const hidl_vec<hal::V1_2::Extension>& extensions) {
     return convertVec(extensions);
 }
 
-Result<std::vector<NativeHandle>> convert(const hidl_vec<hidl_handle>& handles) {
+GeneralResult<std::vector<NativeHandle>> convert(const hidl_vec<hidl_handle>& handles) {
     return convertVec(handles);
 }
 
-Result<std::vector<OutputShape>> convert(const hidl_vec<hal::V1_2::OutputShape>& outputShapes) {
+GeneralResult<std::vector<OutputShape>> convert(
+        const hidl_vec<hal::V1_2::OutputShape>& outputShapes) {
     return convertVec(outputShapes);
 }
 
@@ -278,24 +282,24 @@
 
 using utils::convert;
 
-nn::Result<V1_0::OperandLifeTime> convert(const nn::Operand::LifeTime& lifetime) {
+nn::GeneralResult<V1_0::OperandLifeTime> convert(const nn::Operand::LifeTime& lifetime) {
     return V1_0::utils::convert(lifetime);
 }
 
-nn::Result<V1_0::PerformanceInfo> convert(
+nn::GeneralResult<V1_0::PerformanceInfo> convert(
         const nn::Capabilities::PerformanceInfo& performanceInfo) {
     return V1_0::utils::convert(performanceInfo);
 }
 
-nn::Result<V1_0::DataLocation> convert(const nn::DataLocation& location) {
+nn::GeneralResult<V1_0::DataLocation> convert(const nn::DataLocation& location) {
     return V1_0::utils::convert(location);
 }
 
-nn::Result<hidl_vec<uint8_t>> convert(const nn::Model::OperandValues& operandValues) {
+nn::GeneralResult<hidl_vec<uint8_t>> convert(const nn::Model::OperandValues& operandValues) {
     return V1_0::utils::convert(operandValues);
 }
 
-nn::Result<hidl_memory> convert(const nn::Memory& memory) {
+nn::GeneralResult<hidl_memory> convert(const nn::Memory& memory) {
     return V1_0::utils::convert(memory);
 }
 
@@ -303,7 +307,7 @@
 using ConvertOutput = std::decay_t<decltype(convert(std::declval<Input>()).value())>;
 
 template <typename Type>
-nn::Result<hidl_vec<ConvertOutput<Type>>> convertVec(const std::vector<Type>& arguments) {
+nn::GeneralResult<hidl_vec<ConvertOutput<Type>>> convertVec(const std::vector<Type>& arguments) {
     hidl_vec<ConvertOutput<Type>> halObject(arguments.size());
     for (size_t i = 0; i < arguments.size(); ++i) {
         halObject[i] = NN_TRY(convert(arguments[i]));
@@ -312,22 +316,23 @@
 }
 
 template <typename Type>
-nn::Result<hidl_vec<ConvertOutput<Type>>> convert(const std::vector<Type>& arguments) {
+nn::GeneralResult<hidl_vec<ConvertOutput<Type>>> convert(const std::vector<Type>& arguments) {
     return convertVec(arguments);
 }
 
-nn::Result<Operand::ExtraParams> makeExtraParams(nn::Operand::NoParams /*noParams*/) {
+nn::GeneralResult<Operand::ExtraParams> makeExtraParams(nn::Operand::NoParams /*noParams*/) {
     return Operand::ExtraParams{};
 }
 
-nn::Result<Operand::ExtraParams> makeExtraParams(
+nn::GeneralResult<Operand::ExtraParams> makeExtraParams(
         const nn::Operand::SymmPerChannelQuantParams& channelQuant) {
     Operand::ExtraParams ret;
     ret.channelQuant(NN_TRY(convert(channelQuant)));
     return ret;
 }
 
-nn::Result<Operand::ExtraParams> makeExtraParams(const nn::Operand::ExtensionParams& extension) {
+nn::GeneralResult<Operand::ExtraParams> makeExtraParams(
+        const nn::Operand::ExtensionParams& extension) {
     Operand::ExtraParams ret;
     ret.extension(extension);
     return ret;
@@ -335,28 +340,29 @@
 
 }  // anonymous namespace
 
-nn::Result<OperandType> convert(const nn::OperandType& operandType) {
+nn::GeneralResult<OperandType> convert(const nn::OperandType& operandType) {
     return static_cast<OperandType>(operandType);
 }
 
-nn::Result<OperationType> convert(const nn::OperationType& operationType) {
+nn::GeneralResult<OperationType> convert(const nn::OperationType& operationType) {
     return static_cast<OperationType>(operationType);
 }
 
-nn::Result<DeviceType> convert(const nn::DeviceType& deviceType) {
+nn::GeneralResult<DeviceType> convert(const nn::DeviceType& deviceType) {
     switch (deviceType) {
         case nn::DeviceType::UNKNOWN:
-            return NN_ERROR() << "Invalid DeviceType UNKNOWN";
+            return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE) << "Invalid DeviceType UNKNOWN";
         case nn::DeviceType::OTHER:
         case nn::DeviceType::CPU:
         case nn::DeviceType::GPU:
         case nn::DeviceType::ACCELERATOR:
             return static_cast<DeviceType>(deviceType);
     }
-    return NN_ERROR() << "Invalid DeviceType " << underlyingType(deviceType);
+    return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
+           << "Invalid DeviceType " << underlyingType(deviceType);
 }
 
-nn::Result<Capabilities> convert(const nn::Capabilities& capabilities) {
+nn::GeneralResult<Capabilities> convert(const nn::Capabilities& capabilities) {
     std::vector<nn::Capabilities::OperandPerformance> operandPerformance;
     operandPerformance.reserve(capabilities.operandPerformance.asVector().size());
     std::copy_if(capabilities.operandPerformance.asVector().begin(),
@@ -375,7 +381,7 @@
     };
 }
 
-nn::Result<Capabilities::OperandPerformance> convert(
+nn::GeneralResult<Capabilities::OperandPerformance> convert(
         const nn::Capabilities::OperandPerformance& operandPerformance) {
     return Capabilities::OperandPerformance{
             .type = NN_TRY(convert(operandPerformance.type)),
@@ -383,7 +389,7 @@
     };
 }
 
-nn::Result<Operation> convert(const nn::Operation& operation) {
+nn::GeneralResult<Operation> convert(const nn::Operation& operation) {
     return Operation{
             .type = NN_TRY(convert(operation.type)),
             .inputs = operation.inputs,
@@ -391,7 +397,7 @@
     };
 }
 
-nn::Result<SymmPerChannelQuantParams> convert(
+nn::GeneralResult<SymmPerChannelQuantParams> convert(
         const nn::Operand::SymmPerChannelQuantParams& symmPerChannelQuantParams) {
     return SymmPerChannelQuantParams{
             .scales = symmPerChannelQuantParams.scales,
@@ -399,7 +405,7 @@
     };
 }
 
-nn::Result<Operand> convert(const nn::Operand& operand) {
+nn::GeneralResult<Operand> convert(const nn::Operand& operand) {
     return Operand{
             .type = NN_TRY(convert(operand.type)),
             .dimensions = operand.dimensions,
@@ -412,13 +418,14 @@
     };
 }
 
-nn::Result<Operand::ExtraParams> convert(const nn::Operand::ExtraParams& extraParams) {
+nn::GeneralResult<Operand::ExtraParams> convert(const nn::Operand::ExtraParams& extraParams) {
     return std::visit([](const auto& x) { return makeExtraParams(x); }, extraParams);
 }
 
-nn::Result<Model> convert(const nn::Model& model) {
+nn::GeneralResult<Model> convert(const nn::Model& model) {
     if (!hal::utils::hasNoPointerData(model)) {
-        return NN_ERROR() << "Model cannot be converted because it contains pointer-based memory";
+        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+               << "Model cannot be converted because it contains pointer-based memory";
     }
 
     auto operands = NN_TRY(convert(model.main.operands));
@@ -443,7 +450,7 @@
     };
 }
 
-nn::Result<Model::ExtensionNameAndPrefix> convert(
+nn::GeneralResult<Model::ExtensionNameAndPrefix> convert(
         const nn::Model::ExtensionNameAndPrefix& extensionNameAndPrefix) {
     return Model::ExtensionNameAndPrefix{
             .name = extensionNameAndPrefix.name,
@@ -451,27 +458,27 @@
     };
 }
 
-nn::Result<OutputShape> convert(const nn::OutputShape& outputShape) {
+nn::GeneralResult<OutputShape> convert(const nn::OutputShape& outputShape) {
     return OutputShape{.dimensions = outputShape.dimensions,
                        .isSufficient = outputShape.isSufficient};
 }
 
-nn::Result<MeasureTiming> convert(const nn::MeasureTiming& measureTiming) {
+nn::GeneralResult<MeasureTiming> convert(const nn::MeasureTiming& measureTiming) {
     return static_cast<MeasureTiming>(measureTiming);
 }
 
-nn::Result<Timing> convert(const nn::Timing& timing) {
+nn::GeneralResult<Timing> convert(const nn::Timing& timing) {
     return Timing{.timeOnDevice = timing.timeOnDevice, .timeInDriver = timing.timeInDriver};
 }
 
-nn::Result<Extension> convert(const nn::Extension& extension) {
+nn::GeneralResult<Extension> convert(const nn::Extension& extension) {
     return Extension{
             .name = extension.name,
             .operandTypes = NN_TRY(convert(extension.operandTypes)),
     };
 }
 
-nn::Result<Extension::OperandTypeInformation> convert(
+nn::GeneralResult<Extension::OperandTypeInformation> convert(
         const nn::Extension::OperandTypeInformation& operandTypeInformation) {
     return Extension::OperandTypeInformation{
             .type = operandTypeInformation.type,
@@ -480,22 +487,22 @@
     };
 }
 
-nn::Result<hidl_handle> convert(const nn::NativeHandle& handle) {
+nn::GeneralResult<hidl_handle> convert(const nn::NativeHandle& handle) {
     const auto hidlHandle = hidl_handle(handle->handle());
     // Copy memory to force the native_handle_t to be copied.
     auto copiedHandle = hidlHandle;
     return copiedHandle;
 }
 
-nn::Result<hidl_vec<Extension>> convert(const std::vector<nn::Extension>& extensions) {
+nn::GeneralResult<hidl_vec<Extension>> convert(const std::vector<nn::Extension>& extensions) {
     return convertVec(extensions);
 }
 
-nn::Result<hidl_vec<hidl_handle>> convert(const std::vector<nn::NativeHandle>& handles) {
+nn::GeneralResult<hidl_vec<hidl_handle>> convert(const std::vector<nn::NativeHandle>& handles) {
     return convertVec(handles);
 }
 
-nn::Result<hidl_vec<OutputShape>> convert(const std::vector<nn::OutputShape>& outputShapes) {
+nn::GeneralResult<hidl_vec<OutputShape>> convert(const std::vector<nn::OutputShape>& outputShapes) {
     return convertVec(outputShapes);
 }
 
diff --git a/neuralnetworks/1.2/utils/src/Device.cpp b/neuralnetworks/1.2/utils/src/Device.cpp
new file mode 100644
index 0000000..ca236f1
--- /dev/null
+++ b/neuralnetworks/1.2/utils/src/Device.cpp
@@ -0,0 +1,318 @@
+/*
+ * 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 "Device.h"
+
+#include "Callbacks.h"
+#include "Conversions.h"
+#include "Utils.h"
+
+#include <android/hardware/neuralnetworks/1.0/types.h>
+#include <android/hardware/neuralnetworks/1.1/types.h>
+#include <android/hardware/neuralnetworks/1.2/IDevice.h>
+#include <android/hardware/neuralnetworks/1.2/types.h>
+#include <nnapi/IBuffer.h>
+#include <nnapi/IDevice.h>
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/OperandTypes.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/1.1/Conversions.h>
+#include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/HandleError.h>
+#include <nnapi/hal/ProtectCallback.h>
+
+#include <functional>
+#include <memory>
+#include <optional>
+#include <string>
+#include <vector>
+
+namespace android::hardware::neuralnetworks::V1_2::utils {
+
+nn::GeneralResult<std::string> initVersionString(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 =
+                    validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+            result = NN_ERROR(canonical) << "getVersionString failed with " << toString(status);
+        } else {
+            result = versionString;
+        }
+    };
+
+    const auto ret = device->getVersionString(cb);
+    NN_TRY(hal::utils::handleTransportError(ret));
+
+    return result;
+}
+
+nn::GeneralResult<nn::DeviceType> initDeviceType(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 =
+                    validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+            result = NN_ERROR(canonical) << "getDeviceType failed with " << toString(status);
+        } else {
+            result = nn::convert(deviceType);
+        }
+    };
+
+    const auto ret = device->getType(cb);
+    NN_TRY(hal::utils::handleTransportError(ret));
+
+    return result;
+}
+
+nn::GeneralResult<std::vector<nn::Extension>> initExtensions(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 =
+                    validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+            result = NN_ERROR(canonical) << "getExtensions failed with " << toString(status);
+        } else {
+            result = nn::convert(extensions);
+        }
+    };
+
+    const auto ret = device->getSupportedExtensions(cb);
+    NN_TRY(hal::utils::handleTransportError(ret));
+
+    return result;
+}
+
+nn::GeneralResult<nn::Capabilities> initCapabilities(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 =
+                    validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+            result = NN_ERROR(canonical) << "getCapabilities_1_2 failed with " << toString(status);
+        } else {
+            result = validatedConvertToCanonical(capabilities);
+        }
+    };
+
+    const auto ret = device->getCapabilities_1_2(cb);
+    NN_TRY(hal::utils::handleTransportError(ret));
+
+    return result;
+}
+
+nn::GeneralResult<std::pair<uint32_t, uint32_t>> initNumberOfCacheFilesNeeded(
+        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 =
+                    validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+            result = NN_ERROR(canonical)
+                     << "getNumberOfCacheFilesNeeded failed with " << toString(status);
+        } else {
+            result = std::make_pair(numModelCache, numDataCache);
+        }
+    };
+
+    const auto ret = device->getNumberOfCacheFilesNeeded(cb);
+    NN_TRY(hal::utils::handleTransportError(ret));
+
+    return result;
+}
+
+nn::GeneralResult<std::shared_ptr<const Device>> Device::create(std::string name,
+                                                                sp<V1_2::IDevice> device) {
+    if (name.empty()) {
+        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+               << "V1_2::utils::Device::create must have non-empty name";
+    }
+    if (device == nullptr) {
+        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+               << "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 deathHandler = NN_TRY(hal::utils::DeathHandler::create(device));
+    return std::make_shared<const Device>(
+            PrivateConstructorTag{}, std::move(name), std::move(versionString), deviceType,
+            std::move(extensions), std::move(capabilities), numberOfCacheFilesNeeded,
+            std::move(device), std::move(deathHandler));
+}
+
+Device::Device(PrivateConstructorTag /*tag*/, std::string name, std::string versionString,
+               nn::DeviceType deviceType, std::vector<nn::Extension> extensions,
+               nn::Capabilities capabilities,
+               std::pair<uint32_t, uint32_t> numberOfCacheFilesNeeded, sp<V1_2::IDevice> device,
+               hal::utils::DeathHandler deathHandler)
+    : kName(std::move(name)),
+      kVersionString(std::move(versionString)),
+      kDeviceType(deviceType),
+      kExtensions(std::move(extensions)),
+      kCapabilities(std::move(capabilities)),
+      kNumberOfCacheFilesNeeded(numberOfCacheFilesNeeded),
+      kDevice(std::move(device)),
+      kDeathHandler(std::move(deathHandler)) {}
+
+const std::string& Device::getName() const {
+    return kName;
+}
+
+const std::string& Device::getVersionString() const {
+    return kVersionString;
+}
+
+nn::Version Device::getFeatureLevel() const {
+    return nn::Version::ANDROID_Q;
+}
+
+nn::DeviceType Device::getType() const {
+    return kDeviceType;
+}
+
+const std::vector<nn::Extension>& Device::getSupportedExtensions() const {
+    return kExtensions;
+}
+
+const nn::Capabilities& Device::getCapabilities() const {
+    return kCapabilities;
+}
+
+std::pair<uint32_t, uint32_t> Device::getNumberOfCacheFilesNeeded() const {
+    return kNumberOfCacheFilesNeeded;
+}
+
+nn::GeneralResult<void> Device::wait() const {
+    const auto ret = kDevice->ping();
+    return hal::utils::handleTransportError(ret);
+}
+
+nn::GeneralResult<std::vector<bool>> Device::getSupportedOperations(const nn::Model& model) const {
+    // Ensure that model is ready for IPC.
+    std::optional<nn::Model> maybeModelInShared;
+    const nn::Model& modelInShared =
+            NN_TRY(hal::utils::flushDataFromPointerToShared(&model, &maybeModelInShared));
+
+    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 =
+                    validatedConvertToCanonical(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;
+        }
+    };
+
+    const auto ret = kDevice->getSupportedOperations_1_2(hidlModel, cb);
+    NN_TRY(hal::utils::handleTransportError(ret));
+
+    return result;
+}
+
+nn::GeneralResult<nn::SharedPreparedModel> Device::prepareModel(
+        const nn::Model& model, nn::ExecutionPreference preference, nn::Priority /*priority*/,
+        nn::OptionalTimePoint /*deadline*/, const std::vector<nn::NativeHandle>& modelCache,
+        const std::vector<nn::NativeHandle>& dataCache, const nn::CacheToken& token) const {
+    // Ensure that model is ready for IPC.
+    std::optional<nn::Model> maybeModelInShared;
+    const nn::Model& modelInShared =
+            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 hidlModelCache = NN_TRY(convert(modelCache));
+    const auto hidlDataCache = NN_TRY(convert(dataCache));
+    const auto hidlToken = token;
+
+    const auto cb = sp<PreparedModelCallback>::make();
+    const auto scoped = kDeathHandler.protectCallback(cb.get());
+
+    const auto ret = kDevice->prepareModel_1_2(hidlModel, hidlPreference, hidlModelCache,
+                                               hidlDataCache, hidlToken, cb);
+    const auto status = NN_TRY(hal::utils::handleTransportError(ret));
+    if (status != V1_0::ErrorStatus::NONE) {
+        const auto canonical =
+                validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+        return NN_ERROR(canonical) << "prepareModel_1_2 failed with " << toString(status);
+    }
+
+    return cb->get();
+}
+
+nn::GeneralResult<nn::SharedPreparedModel> Device::prepareModelFromCache(
+        nn::OptionalTimePoint /*deadline*/, const std::vector<nn::NativeHandle>& modelCache,
+        const std::vector<nn::NativeHandle>& 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 cb = sp<PreparedModelCallback>::make();
+    const auto scoped = kDeathHandler.protectCallback(cb.get());
+
+    const auto ret = kDevice->prepareModelFromCache(hidlModelCache, hidlDataCache, hidlToken, cb);
+    const auto status = NN_TRY(hal::utils::handleTransportError(ret));
+    if (status != V1_0::ErrorStatus::NONE) {
+        const auto canonical =
+                validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+        return NN_ERROR(canonical) << "prepareModelFromCache failed with " << toString(status);
+    }
+
+    return cb->get();
+}
+
+nn::GeneralResult<nn::SharedBuffer> Device::allocate(
+        const nn::BufferDesc& /*desc*/,
+        const std::vector<nn::SharedPreparedModel>& /*preparedModels*/,
+        const std::vector<nn::BufferRole>& /*inputRoles*/,
+        const std::vector<nn::BufferRole>& /*outputRoles*/) const {
+    return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
+           << "IDevice::allocate not supported on 1.2 HAL service";
+}
+
+}  // namespace android::hardware::neuralnetworks::V1_2::utils
diff --git a/neuralnetworks/1.2/utils/src/PreparedModel.cpp b/neuralnetworks/1.2/utils/src/PreparedModel.cpp
new file mode 100644
index 0000000..ff9db21
--- /dev/null
+++ b/neuralnetworks/1.2/utils/src/PreparedModel.cpp
@@ -0,0 +1,161 @@
+/*
+ * 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 "PreparedModel.h"
+
+#include "Callbacks.h"
+#include "Conversions.h"
+#include "Utils.h"
+
+#include <android/hardware/neuralnetworks/1.0/types.h>
+#include <android/hardware/neuralnetworks/1.1/types.h>
+#include <android/hardware/neuralnetworks/1.2/IPreparedModel.h>
+#include <android/hardware/neuralnetworks/1.2/types.h>
+#include <nnapi/IPreparedModel.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/1.0/Conversions.h>
+#include <nnapi/hal/CommonUtils.h>
+#include <nnapi/hal/HandleError.h>
+#include <nnapi/hal/ProtectCallback.h>
+
+#include <memory>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+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(validatedConvertToCanonical(outputShapes)),
+                          NN_TRY(validatedConvertToCanonical(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) {
+    if (preparedModel == nullptr) {
+        return NN_ERROR(nn::ErrorStatus::INVALID_ARGUMENT)
+               << "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));
+}
+
+PreparedModel::PreparedModel(PrivateConstructorTag /*tag*/, sp<V1_2::IPreparedModel> preparedModel,
+                             hal::utils::DeathHandler deathHandler)
+    : 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 =
+                    validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+            result = NN_ERROR(canonical) << "executeSynchronously failed with " << toString(status);
+        } else {
+            result = convertExecutionResults(outputShapes, timing);
+        }
+    };
+
+    const auto ret = kPreparedModel->executeSynchronously(request, measure, cb);
+    NN_TRY(hal::utils::makeExecutionFailure(hal::utils::handleTransportError(ret)));
+
+    return result;
+}
+
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>>
+PreparedModel::executeAsynchronously(const V1_0::Request& request, MeasureTiming measure) const {
+    const auto cb = sp<ExecutionCallback>::make();
+    const auto scoped = kDeathHandler.protectCallback(cb.get());
+
+    const auto ret = kPreparedModel->execute_1_2(request, measure, cb);
+    const auto status =
+            NN_TRY(hal::utils::makeExecutionFailure(hal::utils::handleTransportError(ret)));
+    if (status != V1_0::ErrorStatus::NONE) {
+        const auto canonical =
+                validatedConvertToCanonical(status).value_or(nn::ErrorStatus::GENERAL_FAILURE);
+        return NN_ERROR(canonical) << "execute failed with " << toString(status);
+    }
+
+    return cb->get();
+}
+
+nn::ExecutionResult<std::pair<std::vector<nn::OutputShape>, nn::Timing>> PreparedModel::execute(
+        const nn::Request& request, nn::MeasureTiming measure,
+        const nn::OptionalTimePoint& /*deadline*/,
+        const nn::OptionalTimeoutDuration& /*loopTimeoutDuration*/) const {
+    // Ensure that request is ready for IPC.
+    std::optional<nn::Request> maybeRequestInShared;
+    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 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;
+
+    // Execute synchronously if allowed.
+    if (preferSynchronous) {
+        result = executeSynchronously(hidlRequest, hidlMeasure);
+    }
+
+    // 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;
+}
+
+nn::GeneralResult<std::pair<nn::SyncFence, nn::ExecuteFencedInfoCallback>>
+PreparedModel::executeFenced(
+        const nn::Request& /*request*/, const std::vector<nn::SyncFence>& /*waitFor*/,
+        nn::MeasureTiming /*measure*/, const nn::OptionalTimePoint& /*deadline*/,
+        const nn::OptionalTimeoutDuration& /*loopTimeoutDuration*/,
+        const nn::OptionalTimeoutDuration& /*timeoutDurationAfterFence*/) const {
+    return NN_ERROR(nn::ErrorStatus::GENERAL_FAILURE)
+           << "IPreparedModel::executeFenced is not supported on 1.2 HAL service";
+}
+
+std::any PreparedModel::getUnderlyingResource() const {
+    sp<V1_0::IPreparedModel> resource = kPreparedModel;
+    return resource;
+}
+
+}  // namespace android::hardware::neuralnetworks::V1_2::utils
diff --git a/neuralnetworks/1.2/utils/src/Service.cpp b/neuralnetworks/1.2/utils/src/Service.cpp
new file mode 100644
index 0000000..110188f
--- /dev/null
+++ b/neuralnetworks/1.2/utils/src/Service.cpp
@@ -0,0 +1,41 @@
+/*
+ * 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 "Service.h"
+
+#include <nnapi/IDevice.h>
+#include <nnapi/Result.h>
+#include <nnapi/Types.h>
+#include <nnapi/hal/ResilientDevice.h>
+#include <string>
+#include "Device.h"
+
+namespace android::hardware::neuralnetworks::V1_2::utils {
+
+nn::GeneralResult<nn::SharedDevice> getDevice(const std::string& name) {
+    hal::utils::ResilientDevice::Factory makeDevice =
+            [name](bool blocking) -> nn::GeneralResult<nn::SharedDevice> {
+        auto service = blocking ? IDevice::getService(name) : IDevice::tryGetService(name);
+        if (service == nullptr) {
+            return NN_ERROR() << (blocking ? "getService" : "tryGetService") << " returned nullptr";
+        }
+        return Device::create(name, std::move(service));
+    };
+
+    return hal::utils::ResilientDevice::create(std::move(makeDevice));
+}
+
+}  // namespace android::hardware::neuralnetworks::V1_2::utils