diff --git a/audio/README.md b/audio/README.md
index 1938ad4..3f40d72 100644
--- a/audio/README.md
+++ b/audio/README.md
@@ -2,10 +2,29 @@
 
 Directory structure of the audio HAL related code.
 
-Run `common/all-versions/copyHAL.sh` to create a new version of the audio HAL
-based on an existing one.
+## Directory Structure for AIDL audio HAL
 
-## Directory Structure
+The AIDL version is located inside `aidl` directory. The tree below explains
+the role of each subdirectory:
+
+* `aidl_api` — snapshots of the API created each Android release. Every
+  release, the current version of the API becomes "frozen" and gets assigned
+  the next version number. If the API needs further modifications, they are
+  made on the "current" version. After making modifications, run
+  `m <package name>-update-api` to update the snapshot of the "current"
+  version.
+* `android/hardware/audio/common` — data structures and interfaces shared
+  between various HALs: BT HAL, core and effects audio HALs.
+* `android/hardware/audio/core` — data structures and interfaces of the
+  core audio HAL.
+* `default` — the default, reference implementation of the audio HAL service.
+* `vts` — VTS tests for the AIDL HAL.
+
+## Directory Structure for HIDL audio HAL
+
+Run `common/all-versions/copyHAL.sh` to create a new version of the HIDL audio
+HAL based on an existing one. Note that this isn't possible since Android T
+release. Android U and above uses AIDL audio HAL.
 
 * `2.0` — version 2.0 of the core HIDL API. Note that `.hal` files
   can not be moved into the `core` directory because that would change
diff --git a/audio/aidl/aidl_api/android.hardware.audio.effect/current/android/hardware/audio/effect/NoiseSuppression.aidl b/audio/aidl/aidl_api/android.hardware.audio.effect/current/android/hardware/audio/effect/NoiseSuppression.aidl
index 397f897..1cf92ef 100644
--- a/audio/aidl/aidl_api/android.hardware.audio.effect/current/android/hardware/audio/effect/NoiseSuppression.aidl
+++ b/audio/aidl/aidl_api/android.hardware.audio.effect/current/android/hardware/audio/effect/NoiseSuppression.aidl
@@ -50,5 +50,6 @@
     LOW,
     MEDIUM,
     HIGH,
+    VERY_HIGH,
   }
 }
diff --git a/audio/aidl/android/hardware/audio/effect/NoiseSuppression.aidl b/audio/aidl/android/hardware/audio/effect/NoiseSuppression.aidl
index 946fa87..9969a0b 100644
--- a/audio/aidl/android/hardware/audio/effect/NoiseSuppression.aidl
+++ b/audio/aidl/android/hardware/audio/effect/NoiseSuppression.aidl
@@ -62,7 +62,7 @@
      * suppression, NsConfig::SuppressionLevel::k12dB for MEDIUM, and
      * NsConfig::SuppressionLevel::k18dB for HIGH.
      */
-    @VintfStability @Backing(type="int") enum Level { LOW, MEDIUM, HIGH }
+    @VintfStability @Backing(type="int") enum Level { LOW, MEDIUM, HIGH, VERY_HIGH }
 
     /**
      * The NS level.
diff --git a/bluetooth/hci/h4_protocol.cc b/bluetooth/hci/h4_protocol.cc
index 97ba7aa..51a624f 100644
--- a/bluetooth/hci/h4_protocol.cc
+++ b/bluetooth/hci/h4_protocol.cc
@@ -58,10 +58,8 @@
   while (1) {
     ret = TEMP_FAILURE_RETRY(writev(uart_fd_, iov, 2));
     if (ret == -1) {
-      if (errno == EAGAIN) {
-        ALOGE("%s error writing to UART (%s)", __func__, strerror(errno));
-        continue;
-      }
+      LOG_ALWAYS_FATAL("%s error writing to UART (%s)", __func__,
+                       strerror(errno));
     } else if (ret == 0) {
       // Nothing written :(
       ALOGE("%s zero bytes written - something went wrong...", __func__);