diff --git a/android/hal-ipc-api.txt b/android/hal-ipc-api.txt
index 0518c2f..6bf9af3 100644
--- a/android/hal-ipc-api.txt
+++ b/android/hal-ipc-api.txt
@@ -124,12 +124,16 @@ Core Service (ID 0)
 	Opcode 0x01 - Register module command/response
 
 		Command parameters: Service id (1 octet)
+		                    Mode (1 octet)
 		Response parameters: <none>
 
 		In case a command is sent for an undeclared service ID, it will
 		be rejected. Also there will be no notifications for undeclared
 		service ID.
 
+		Valid Mode values: 0x00 = Default Mode
+		                   0xXX = as defined by service
+
 		In case of an error, the error response will be returned.
 
 	Opcode 0x02 - Unregister module command/response
@@ -749,6 +753,8 @@ Bluetooth Handsfree HAL (ID 5)
 
 Android HAL name: "handsfree" (BT_PROFILE_HANDSFREE_ID)
 
+	Service modes:               0x01 = Headset Profile only mode
+
 	Opcode 0x00 - Error response
 
 		Response parameters: Status (1 octet)