Radio removal keys (two U-shaped metal tools, ~$5 online) or stiff wires.

(by various developers – scan with antivirus before use)

Write down the full 14-digit serial number (e.g., VWZ1Z2G1234567 ). 2.2 Alternative: Using the "Hidden Menu" (Without Removal – Limited Success) Some RCD310 firmware versions show the serial number on screen.