ASRock Z270 Supercarrier - blackscreen 09/d0, cannot switch to backup BIOS

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Feb 2, 2017
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I have an ASRock Z270 Supercarrier and used the Internet Flash utility in UEFI setup to upgrade the BIOS from 1.10 to 1.11. The upgrade process completed successfully and no errors were reported. However, when the computer rebooted with the new BIOS, it just hung with a blackscreen. I have rebooted the system over 20 times, with the same result. The boot process runs for about 15 seconds, the Dr. Debug LED settles on 09 or d0, and remains in that hung state.

According to the manual, "after several failed boot attempts, the backup BIOS will take over" -- but this doesn't seem to be happening. It still boots from the active BIOS (BIOS_A_LED is on). I also tried unplugging the computer and depressing the clear CMOS button for over 10 seconds, but that didn't seem to have any affect.

Is there any way that I can force a switch to BIOS B, or alternatively, downgrade BIOS A back to 1.10? The motherboard was working fine with 1.10 before I upgraded it to 1.11.
 
Switch to the working BIOS, then before you flash, flip the BIOS switch to the non-working one.
 
Switch to the working BIOS, then before you flash, flip the BIOS switch to the non-working one.

That's the problem -- I don't know how to do that. There's no switch on the Z270 Supercarrier to go from BIOS A to BIOS B, as far as I can tell. There are some jumpers near BIOS_A_LED and BIOS_B_LED, but I can't find any documentation that indicates whether they enable switching the BIOS.
 
Ah, looks like the board doesn't have a manual switch to toggle between either BIOS. Page 92 of the manual:
This motherboard has two BIOS chips, an active BIOS (BIOS_A) and a backup BIOS (BIOS_B), which enhances the safety and stability of your system. Use “Secure Backup UEFI” to duplicate a working copy of the BIOS files to the active BIOS to ensure normal system operation. Normally, the system will work on the active BIOS. However if the active BIOS is corrupted or damaged, after several failed boot attempts, the backup BIOS will take over. For safety issues, users are not able to update the backup BIOS manually. Users may refer to the BIOS LEDs (BIOS_A_LED or BIOS_B_LED) to identify which BIOS is currently activated.
 
Ah, looks like the board doesn't have a manual switch to toggle between either BIOS. Page 92 of the manual:

Right. It's been over 30 failed boot attempts now, so I'm trying to get a better idea of what they mean by "after several failed boot attempts, the backup BIOS will take over" (or find some other way to force the switch). BIOS_A_LED is still on.
 
Sounds like a bad implementation on ASRock's part. If the board is recent (should be) maybe try an RMA?
 
Sounds like a bad implementation on ASRock's part. If the board is recent (should be) maybe try an RMA?

I opened a support case with them this morning, haven't heard back yet. If I can't get a resolution then I may have to go that route. Would be nice to avoid that hassle though if possible.
 
I found a jumper (undocumented) to switch to the backup BIOS -- D_BIOS_TEST1, located above CHA_FAN3. Now I'm able to boot into BIOS B, but I have another problem. It boots and quickly shuts down 1-2 times, then boots and does the Secure Backup UEFI B->A until the progress indicator reads 99%, then it shuts down, then boots and shuts down quickly again, then boots back into the secure UEFI backup and repeats this in a loop.

I've tried interrupting this loop by powering off the computer after the first or second reboot after the 99% done, and then removing the jumper. It switches back to BIOS A, but I get the same 09/d0 lockup with BIOS A again :-( It seems like the secure backup UEFI B->A didn't work.

Thinking about what other options might be possible.
 
Good news -- I removed all but one of my RAM cards and was able to boot up with BIOS A, which was on 1.11 (looks like the secure backup B->A didn't have any effect). I attached a FAT32 USB stick with the 1.10 BIOS file and used the UEFI Instant Flash tool to successfully downgrade BIOS A. I then added back my other RAM cards and successfully booted the system just like it was before. Problem solved!
 
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Glad you got it working, 2 things to take from this:- Only update the BIOS if you need to and always do it from within the BIOS
 
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