[SOLVED] After 10.13.1->10.13.4 update, BIOS just hangs

[pumpichank]

I upgraded from 10.12.6 to 10.13.1 just fine, but after applying the 10.13.4 upgrade and rebooting, my motherboard never gets past the BIOS screen. It says "Please press DEL or F2 to enter UEFI BIOS setting" but it completely ignores all keyboard input. So I can't get to the BIOS settings and it never gets past that in the boot process.

How could the 10.13.1 -> 10.13.4 update break my BIOS? Is it possible that the update messed up my EFI partition and that's why it's stuck?

Any ideas about how I can get out of this? I can't even get to boot a USB, recovery, cloned backup drive, etc. I'm thinking about pulling all the hard drives just so I can get back into the BIOS, but I don't know if that'll help.

 

[P1LGRIM]

Any ideas about how I can get out of this?

CMOS reset.

 

[pumpichank]

CMOS reset.

Thanks for the suggestion!

I just tried that and it didn't help. I used the procedure described in the Gryphon Z97 manual. Turned off computer, removed power cable. Moved CLRTC jumpers from pins 1-2 to pins 2-3. Waited 10+ seconds. Moved jumpers back, plugged everything back in, powered up and held DEL button. It still hangs on the BIOS boot screen. Also tried procedure with battery removed as suggested by the manual. Neither helped.

Is there anything else I'm missing?

 

[pumpichank]

So, what worked is to unplug all SATA devices and do the CMOS reset procedure above. Then I was able to get into the BIOS, update my settings, plug all disks back in, and it booted just fine. It didn't get upgraded to 10.13.4 but I'm trying that now.