diff --git a/android/hal-ipc-api.txt b/android/hal-ipc-api.txt
index 70c451d..53fa5b9 100644
--- a/android/hal-ipc-api.txt
+++ b/android/hal-ipc-api.txt
@@ -1428,6 +1428,12 @@ Android HAL name: "gatt" (BT_PROFILE_GATT_ID)
 		In case of an error, the error response will be returned.
 
 	Opcode 0x02 - Unregister Client command/response
+
+		Command parameters: Client Interface (4 octets)
+		Response parameters: <none>
+
+		In case of an error, the error response will be returned.
+
 	Opcode 0x03 - Scan command/response
 	Opcode 0x04 - Connect Device command/response
 	Opcode 0x05 - Disconnect Device command/response
diff --git a/android/hal-msg.h b/android/hal-msg.h
index 350a75c..7350ba0 100644
--- a/android/hal-msg.h
+++ b/android/hal-msg.h
@@ -523,6 +523,11 @@ struct hal_cmd_gatt_client_register {
 	uint8_t uuid[16];
 } __attribute__((packed));
 
+#define HAL_OP_GATT_CLIENT_UNREGISTER		0x02
+struct hal_cmd_gatt_client_unregister {
+	int32_t client_if;
+} __attribute__((packed));
+
 /* Notifications and confirmations */
 
 #define HAL_POWER_OFF			0x00