Change to FFFD

Author: bouwew

tests/test_usb.py

@@ -673,7 +673,7 @@ async def test_stick_node_join_subscription(
         await stick.set_accept_join_request(True)
 
         # Inject node join request message
-        mock_serial.inject_message(b"00069999999999999999", b"FFFC")
+        mock_serial.inject_message(b"00069999999999999999", b"FFFD")
         self.test_node_join = asyncio.Future()
         unusb_join = stick.subscribe_to_node_events(
             node_event_callback=self.node_join,