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(