Dell Latitude 3420 BIOS - Manufacturing Mode Required

[Jdpaz]

try

It works but serial tag says n/a. Is that how it should be?

[LBTT1121]

1st boot, press F2, write service tag, disable Absolute, save (Apply changes), restart. 2nd boot press Alt+F to exit manufacturing mode

[Jdpaz]

1st boot, press F2, write service tag, disable Absolute, save (Apply changes), restart. 2nd boot press Alt+F to exit manufacturing mode

The option to disable absolute is greyed out.