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

[kartik_subbarao]

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.

[The_Denks]

4 minutes ago, kartik_subbarao said:

-SNIP-

I had a similar problem with an X99 board a while ago.

It seemed to clear itself after about 40 failed boots, and resetting CMOS every 5 boots

 

However, ive never used a 270 chipset board, so maybe be very different

[zMeul]

have you tried putting the working BIOS file on a USB stick (FAT32) and plugging it in?

the mobo should recover from the file .. should

[kartik_subbarao]

UberGameKing -- thanks for the datapoint. I'll try rebooting some more and resetting CMOS some more to see if that triggers the failover to the backup BIOS.

 

zMeul -- thanks for the suggestion. I tried putting the Z270SC_1.10 file on a FAT32 USB stick, plugging it in and booting the system. It didn't seem to have any effect. Dr. Debug still hangs at 09.

[kartik_subbarao]

Good news -- I removed all but one of my RAM cards and was able to boot up with BIOS A. I attached the 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!