[T420] How to enter into the factory mode & engineer mode to check serial number?

03-06-2017
1. FACTORY mode: Press 37951 on remote controller or press “power button” and “left button” on keypad under POWER off mode for 5s
2. ENGINEER mode: Press 37952 on remote controller or press “power button” and “right button” on keypad under POWER off mode for 5s
TOP