Lenovo ThinkPad L420 L421 L520 (BIOS 8GUJ17us) Whitelist
Original (non modified) same version bios SHOULD be flashed at first.
then, after reboot, flash modified bios
Run the WinPhlash 32 or 64 bit, click "Advanced Settings"
then check and uncheck the boxes so it looks like this:
("Flags"...