diff --git a/include/hardware/bt_hh.h b/include/hardware/bt_hh.h
index 09f547b..dad9586 100644
--- a/include/hardware/bt_hh.h
+++ b/include/hardware/bt_hh.h
@@ -99,10 +99,10 @@
  */
 typedef void (* bthh_hid_info_callback)(bt_bdaddr_t *bd_addr, bthh_hid_info_t hid_info);
 
-/** Callback for get/set protocal api.
+/** Callback for get protocol api.
  *  the protocol mode is one of the value from bthh_protocol_mode_t
  */
-typedef void (* bthh_protocol_mode_callback)(bt_bdaddr_t *bd_addr, bthh_status_t hh_status,bthh_protocol_mode_t mode);
+typedef void (* bthh_protocol_mode_callback)(bt_bdaddr_t *bd_addr, bthh_status_t hh_status, bthh_protocol_mode_t mode);
 
 /** Callback for get/set_idle_time api.
  */
@@ -114,6 +114,11 @@
  */
 typedef void (* bthh_get_report_callback)(bt_bdaddr_t *bd_addr, bthh_status_t hh_status, uint8_t* rpt_data, int rpt_size);
 
+/** Callback for set_report/set_protocol api and if error
+ *  occurs for get_report/get_protocol api.
+ */
+typedef void (* bthh_handshake_callback)(bt_bdaddr_t *bd_addr, bthh_status_t hh_status);
+
 
 /** BT-HH callback structure. */
 typedef struct {
@@ -125,6 +130,7 @@
     bthh_idle_time_callback         idle_time_cb;
     bthh_get_report_callback        get_report_cb;
     bthh_virtual_unplug_callback    virtual_unplug_cb;
+    bthh_handshake_callback         handshake_cb;
 
 } bthh_callbacks_t;
 
diff --git a/modules/usbaudio/audio_hw.c b/modules/usbaudio/audio_hw.c
index f33c343..24a2d63 100644
--- a/modules/usbaudio/audio_hw.c
+++ b/modules/usbaudio/audio_hw.c
@@ -212,7 +212,7 @@
 
 err:
     pthread_mutex_unlock(&out->lock);
-
+    pthread_mutex_unlock(&out->dev->lock);
     if (ret != 0) {
         usleep(bytes * 1000000 / audio_stream_frame_size(&stream->common) /
                out_get_sample_rate(&stream->common));