AMD Motherboards - x570 Taichi help, bios update, stuck post code 91

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x570 Taichi help, bios update, stuck post code 91

Printed From: ASRock.com
Category: Technical Support
Forum Name: AMD Motherboards
Forum Description: Question about ASRock AMD motherboards
URL: https://forum.asrock.com/forum_posts.asp?TID=19395
Printed Date: 08 Aug 2025 at 7:00am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: x570 Taichi help, bios update, stuck post code 91

Posted By: willfalcon
Subject: x570 Taichi help, bios update, stuck post code 91
Date Posted: 13 Aug 2021 at 4:59am

I was running bios version 3.80, i downloaded version 4.0 which was the next available so i didnt skip anything, i formatted a usb 8gb drive to FAT32, unzipped the 4.0 bios, moved it to the drive, booted to the bios, went to tools and the instantflash option, it immediately detected the version on the USB drive, i started the update, recived a success message and pressed enter as per the screen instruction to reboot, but the system got stuck at code 91 on the board. i reset the system, same thing code 91. (i dont get anything on the monitor not even a hint that its trying )

I have a 3600x cpu, 4 x 8 gb ram, 6900 xt, all was working prior to flashing the bios.

i have turned the system off, pulled the plug, hit the on button a few times, held in the cmos clear button, booted back up, no difference

what can i do? please help

Replies:

Posted By: Khun_Doug
Date Posted: 13 Aug 2021 at 5:21am

Willfalcon,

On a PC or whatever that is functional, I would download the last BIOS made available. From my checking on that motherboard, there is a version 4.6. Use the motherboard instruction guide on how to prepare the USB flashdrive and then use the motherboard's Flash Back utility to install the new BIOS. Hopefully that new BIOS will get past this error.

Posted By: willfalcon
Date Posted: 13 Aug 2021 at 5:54am

Ii wasnt sure if rolling back a bios was possible as i came across conflicting info via google and the manual doesn't actually say rolling back a bios is ok, it just uses the term flashback, which i would assume is as the name suggests but i like idiot proof and specific wording to actually say yes you can roll back a bios.

i have done exactly that, re flashed 3.80 as per the manual by renaming to creative.rom and immediately i knew it was working as the monitor kicked into life as soon as i pressed the on button for the pc.
i thought ok, lets try bios 4.0 in the same way. nope doesnt work. so either something is wrong with that version of bios or something in that version of bios doesnt like a component in my pc. i find it odd that my monitor reacts immediately to bios version 3.80 when i press the on button, but bios 4.0 does nothing with my monitor.

Can i skip past all bios versions from 3.80 onwards straight to the newest without an issue??

Posted By: Khun_Doug
Date Posted: 13 Aug 2021 at 8:35am

Willfalcon,

There is no reason to go through the various versions of BIOS to reach the final version. From looking at the support page for your motherboard, I believe the latest is rev 4.6 (or 4.8, the page is closed now). You can download that, and use the Flashback tool to install. There is also probably a place within BIOS that allows flashing. I prefer to do it from BIOS myself, as that allows me to see what's happening.

At least you know 3.8 works. Hopefully the 4.6 (or 4.8) will work as well.

Posted By: willfalcon
Date Posted: 13 Aug 2021 at 10:17pm

Khun_Doug wrote:

Willfalcon,

There is no reason to go through the various versions of BIOS to reach the final version. From looking at the support page for your motherboard, I believe the latest is rev 4.6 (or 4.8, the page is closed now). You can download that, and use the Flashback tool to install. There is also probably a place within BIOS that allows flashing. I prefer to do it from BIOS myself, as that allows me to see what's happening.

At least you know 3.8 works. Hopefully the 4.6 (or 4.8) will work as well.

thank you for your help, i have updated to the 4.6 bios and booted up without an issue.. well, technically the bios update hasnt fixed my root problem which is hard drives doing a disappearing act and requiring re initializing and formatting as if it was a brand new drive. its happened twice now in the past few days after i built my system with the new x570, previously i was using an rog b350-f. the only things ive changed is the motherboard, and gpu.

Posted By: Khun_Doug
Date Posted: 14 Aug 2021 at 3:05am

Willfalcon,

Would you describe your hard drive problem in more detail? You say your system was originally running on an Asus ROG motherboard, and you moved that to an Asrock motherboard. What other steps did you take after moving the hardware, and are the symptoms/errors?