I enabled Secure Boot in my M6700. Now I cannot enter UEFI (BIOS) setup. The screen does not show the Dell logo, it's just black. But if I turn the power off and back on, and do not press F2 or F12, and wait, then Windows boots and the screen is normal after that.
I updated the UEFI (BIOS) to A20 before enabling Secure Boot. F2 and F12 were working normally before I enabled Secure Boot.
How can I fix this?
Addendum: I disconnected the CMOS battery in hopes of resetting whatever got messed up. And reconnected the CMOS battery. NOW IT DOESN'T BOOT AT ALL. COMPLETELY BRICKED.
In 2019 Dell released a new firmware update (BIOS/UEFI) and Dell still neglected to delete the malicious options to disable option ROMs and enable secure boot, i.e. the options that damage the hardware to such an extent that this kind of hardware repair is necessary.