diff --git a/nfc/1.0/INfc.hal b/nfc/1.0/INfc.hal
index 1c952db..c6e1511 100644
--- a/nfc/1.0/INfc.hal
+++ b/nfc/1.0/INfc.hal
@@ -27,72 +27,80 @@
      * NCI initialization - ie accept CORE_RESET and subsequent commands through
      * the write() call.
      *
-     * If open() returns 0, the NCI stack will wait for a NfcEvent.OPEN_CPLT
-     * before continuing.
+     * If open() returns NfcStatus::OK, the NCI stack will wait for a
+     * NfcEvent.OPEN_CPLT before continuing.
      *
-     * If open() returns any other value, the NCI stack will stop.
+     * If open() returns NfcStatus::FAILED, the NCI stack will stop.
      *
      */
     @entry
     @callflow(next={"write", "coreInitialized", "prediscover", "powerCycle", "controlGranted"})
-    open(INfcClientCallback clientCallback) generates (int32_t retval);
+    open(INfcClientCallback clientCallback) generates (NfcStatus status);
 
     /*
      * Performs an NCI write.
      *
      * This method may queue writes and return immediately. The only
      * requirement is that the writes are executed in order.
+     *
+     * @return number of bytes written to the NFCC
      */
     @callflow(next={"write", "prediscover", "coreInitialized", "close", "powerCycle",
                     "controlGranted"})
-    write(NfcData data) generates (int32_t retval);
+    write(NfcData data) generates (uint32_t retval);
 
     /*
-     * coreInitialized() is called after the CORE_INIT_RSP is received from the NFCC.
-     * At this time, the HAL can do any chip-specific configuration.
+     * coreInitialized() is called after the CORE_INIT_RSP is received from the
+     * NFCC. At this time, the HAL can do any chip-specific configuration.
      *
-     * If coreInitialized() returns 0, the NCI stack will wait for a NfcEvent.POST_INIT_CPLT
-     * before continuing.
+     * If coreInitialized() returns NfcStatus::OK, the NCI stack will wait for a
+     * NfcEvent.POST_INIT_CPLT before continuing.
      *
-     * If coreInitialized() returns any other value, the NCI stack will continue
-     * immediately.
+     * If coreInitialized() returns NfcStatus::FAILED, the NCI stack will
+     * continue immediately.
      */
     @callflow(next={"write", "prediscover", "close"})
-    coreInitialized(NfcData data) generates (int32_t retval);
+    coreInitialized(NfcData data) generates (NfcStatus status);
 
     /*
      * prediscover is called every time before starting RF discovery.
      * It is a good place to do vendor-specific configuration that must be
      * performed every time RF discovery is about to be started.
      *
-     * If prediscover() returns 0, the NCI stack will wait for a NfcEvent.PREDISCOVER_CPLT
-     * before continuing.
+     * If prediscover() returns NfcStatus::OK, the NCI stack will wait for a
+     * NfcEvent.PREDISCOVER_CPLT before continuing.
      *
-     * If prediscover() returns any other value, the NCI stack will start
+     * If prediscover() returns NfcStatus::FAILED, the NCI stack will start
      * RF discovery immediately.
      */
     @callflow(next={"write", "close", "coreInitialized", "powerCycle", "controlGranted"})
-    prediscover() generates (int32_t retval);
+    prediscover() generates (NfcStatus status);
 
     /*
      * Close the NFC controller. Should free all resources.
+     *
+     * @return NfcStatus::OK on success and NfcStatus::FAILED on error.
      */
     @exit
-    close() generates (int32_t retval);
+    close() generates (NfcStatus status);
 
     /*
      * Grant HAL the exclusive control to send NCI commands.
      * Called in response to NfcEvent.REQUEST_CONTROL.
      * Must only be called when there are no NCI commands pending.
      * NfcEvent.RELEASE_CONTROL will notify when HAL no longer needs exclusive control.
+     *
+     * @return NfcStatus::OK on success and NfcStatus::FAILED on error.
      */
     @callflow(next={"write", "close", "prediscover", "coreInitialized", "powerCycle"})
-    controlGranted() generates (int32_t retval);
+    controlGranted() generates (NfcStatus status);
 
      /*
      * Restart controller by power cyle;
      * NfcEvent.OPEN_CPLT will notify when operation is complete.
+     *
+     * @return NfcStatus::OK on success and NfcStatus::FAILED on error.
      */
     @callflow(next={"write", "coreInitialized", "prediscover", "controlGranted", "close"})
-    powerCycle() generates (int32_t retval);
+    powerCycle() generates (NfcStatus status);
 };
diff --git a/nfc/1.0/default/Nfc.cpp b/nfc/1.0/default/Nfc.cpp
index d3868c1..bee374d 100644
--- a/nfc/1.0/default/Nfc.cpp
+++ b/nfc/1.0/default/Nfc.cpp
@@ -17,34 +17,36 @@
 }
 
 // Methods from ::android::hardware::nfc::V1_0::INfc follow.
-::android::hardware::Return<int32_t> Nfc::open(const sp<INfcClientCallback>& clientCallback)  {
+::android::hardware::Return<NfcStatus> Nfc::open(const sp<INfcClientCallback>& clientCallback)  {
     mCallback = clientCallback;
-    return mDevice->open(mDevice, eventCallback, dataCallback);
+    int ret = mDevice->open(mDevice, eventCallback, dataCallback);
+    return ret == 0 ? NfcStatus::OK : NfcStatus::FAILED;
 }
 
-::android::hardware::Return<int32_t> Nfc::write(const hidl_vec<uint8_t>& data)  {
+::android::hardware::Return<uint32_t> Nfc::write(const hidl_vec<uint8_t>& data)  {
     return mDevice->write(mDevice, data.size(), &data[0]);
 }
 
-::android::hardware::Return<int32_t> Nfc::coreInitialized(const hidl_vec<uint8_t>& data)  {
+::android::hardware::Return<NfcStatus> Nfc::coreInitialized(const hidl_vec<uint8_t>& data)  {
     hidl_vec<uint8_t> copy = data;
-    return mDevice->core_initialized(mDevice, &copy[0]);
+    int ret = mDevice->core_initialized(mDevice, &copy[0]);
+    return ret == 0 ? NfcStatus::OK : NfcStatus::FAILED;
 }
 
-::android::hardware::Return<int32_t> Nfc::prediscover()  {
-    return mDevice->pre_discover(mDevice);
+::android::hardware::Return<NfcStatus> Nfc::prediscover()  {
+    return mDevice->pre_discover(mDevice) ? NfcStatus::FAILED : NfcStatus::OK;
 }
 
-::android::hardware::Return<int32_t> Nfc::close()  {
-    return mDevice->close(mDevice);
+::android::hardware::Return<NfcStatus> Nfc::close()  {
+    return mDevice->close(mDevice) ? NfcStatus::FAILED : NfcStatus::OK;
 }
 
-::android::hardware::Return<int32_t> Nfc::controlGranted()  {
-    return mDevice->control_granted(mDevice);
+::android::hardware::Return<NfcStatus> Nfc::controlGranted()  {
+    return mDevice->control_granted(mDevice) ? NfcStatus::FAILED : NfcStatus::OK;
 }
 
-::android::hardware::Return<int32_t> Nfc::powerCycle()  {
-    return mDevice->power_cycle(mDevice);
+::android::hardware::Return<NfcStatus> Nfc::powerCycle()  {
+    return mDevice->power_cycle(mDevice) ? NfcStatus::FAILED : NfcStatus::OK;
 }
 
 
diff --git a/nfc/1.0/default/Nfc.h b/nfc/1.0/default/Nfc.h
index 5257636..13004a5 100644
--- a/nfc/1.0/default/Nfc.h
+++ b/nfc/1.0/default/Nfc.h
@@ -21,13 +21,13 @@
 
 struct Nfc : public INfc {
   Nfc(nfc_nci_device_t* device);
-  ::android::hardware::Return<int32_t> open(const sp<INfcClientCallback>& clientCallback)  override;
-  ::android::hardware::Return<int32_t> write(const hidl_vec<uint8_t>& data)  override;
-  ::android::hardware::Return<int32_t> coreInitialized(const hidl_vec<uint8_t>& data)  override;
-  ::android::hardware::Return<int32_t> prediscover()  override;
-  ::android::hardware::Return<int32_t> close()  override;
-  ::android::hardware::Return<int32_t> controlGranted()  override;
-  ::android::hardware::Return<int32_t> powerCycle()  override;
+  ::android::hardware::Return<NfcStatus> open(const sp<INfcClientCallback>& clientCallback)  override;
+  ::android::hardware::Return<uint32_t> write(const hidl_vec<uint8_t>& data)  override;
+  ::android::hardware::Return<NfcStatus> coreInitialized(const hidl_vec<uint8_t>& data)  override;
+  ::android::hardware::Return<NfcStatus> prediscover()  override;
+  ::android::hardware::Return<NfcStatus> close()  override;
+  ::android::hardware::Return<NfcStatus> controlGranted()  override;
+  ::android::hardware::Return<NfcStatus> powerCycle()  override;
 
   static void eventCallback(uint8_t event, uint8_t status) {
       if (mCallback != nullptr) {