AB350 Pro4 / GPU passthrough fail / BIOS 5.80
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=12679
Printed Date: 02 Aug 2025 at 5:34am
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com
Topic: AB350 Pro4 / GPU passthrough fail / BIOS 5.80
Posted By: Janux
Subject: AB350 Pro4 / GPU passthrough fail / BIOS 5.80
Date Posted: 16 Oct 2019 at 10:11pm
Hi All. I'm running a dual-GPU Ubuntu Linux machine. I have a QEMU/KVM based VM with Windows 10 inside and I like to run it from within Linux.
My setup worked like a charm for nearly 2 years - I've been running on BIOS v 5.00. From time to time I would have a freeze in Linux which I couldn't resolve via kernel or driver tweaks. I've decided to upgrade the BIOS on the damn motherboard to help resolve this - big mistake...
The computer pretty much died and after CMOS reset, issues with boot and VGA arbitration, I finally recovered everything apart from the being able to pass the GPU to the VM. I believe this is down to a bug in AGESA - specifically I moved to AGESA 0.0.7.2 and then to AGESA Combo-AM4 1.0.0.1.
These threads point to AGESA:
1. https://www.reddit.com/r/Amd/comments/bh3qqz/agesa_0072_pci_quirk/
2. https://www.reddit.com/r/VFIO/comments/bvqxnt/psa_amd_agesa_1001_does_not_fix_the_pci/
3. https://www.reddit.com/r/VFIO/comments/b7249z/asrock_ab350_pro4_downgradevfio_issues/
So in short: whatever I try on the OS side will fail because the GPU can't be powered on while being passed to the VM.
I now have the following choices (and this is where I need your help...):
1. I can try fixing this via OS hacks. Doubt this will work or that a hack exists.
2. I can convert into a dual-boot system. That's extra work and pain of having to reboot to enter the other OS.
3. I can try downgrading the BIOS. ASRock says I can't downgrade below 5.70 now. Really? No way around this?
BIOS list: https://www.asrock.com/mb/AMD/AB350%20Pro4/#BIOS
Rant: I cannot believe the garbage which ASRock and/or AMD released. To have an update and actively discourage users from upgrading because, as a manufacturer, you appreciate how destructive it can be is appalling. Absolutely shocking.
Janux
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Replies:
Posted By: Ray62
Date Posted: 17 Oct 2019 at 2:54am
What CPU and which RAM (exactly) with what speed do you use?
There is something configured not properly on your system, another bios will not help from my point of view.
With a 1000 or 2000 Ryzen the bios with AGESA_Pi_1.0.0.6 should be used, that means: Version 5.40 for your board.
But 5.70 might be ok too, with just the added Athlon 2xxGE series APU support.
Anything newer is only for newer (Matisse) CPUs.
It should be possible to downgrade the bios (but with a windows flash tool), see here:
http://forum.asrock.com/forum_posts.asp?TID=12666&title=downgrade-bios-version
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Asrock Fatal1ty X370 Professional Gaming Offline
Under test:
MSI X570_MEG_ACE | AMD Ryzen 9 3900X | Scythe Mugen5 | 2x16GB F4-3200C14D-32GTZ@3466 | ASUS GeForce GTX 1080 Ti FE
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Posted By: Janux
Date Posted: 17 Oct 2019 at 4:08pm
Right - should've mentioned the specs!
Ryzen 5 1600
RX 570
HD 5500
If I run the tool, do I not risk messing up the BIOS?
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Posted By: Ray62
Date Posted: 18 Oct 2019 at 4:40am
Of course there is a risk. But the user in the mentioned thread gots the flash tool from Asrock support.
There is another, newer thread here in the forum from a user with the same problem:
http://forum.asrock.com/forum_posts.asp?TID=12684&title=x370-taichi-debug-code-55-after-flash-to-560
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Asrock Fatal1ty X370 Professional Gaming Offline
Under test:
MSI X570_MEG_ACE | AMD Ryzen 9 3900X | Scythe Mugen5 | 2x16GB F4-3200C14D-32GTZ@3466 | ASUS GeForce GTX 1080 Ti FE
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Posted By: soulstealer
Date Posted: 18 Oct 2019 at 9:26pm
i have the same board using bios 6.00 with ryzen 1700 and it works perfectly well and better than every other bios i tried.
regarding gpu passthrough, do you have the respective options in bios enabled?
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Posted By: Janux
Date Posted: 18 Oct 2019 at 10:03pm
Yes I do. The exact same setup worked for nearly 1.5 years until I upgraded the BIOS. I made sure that, post CMOS reset, the required options were all enabled.
I've decided to convert to dual boot rather than experiment with the BIOS. I have no desire whatsoever to brick the damn thing - especially not now as I've got other, far more important priorities to focus on and don't want to have to go through the purchase-install-configure cycle again.
Fortunately Linux is a fantastic tool to be working with so I managed, rather easily, to dump the VM images to a single HDD and have since confirmed it all works fine.
The takeaway for me is as follows:
1. I will not buy into a vendor who places restrictions on downgrading. I understand it may be needed sometimes but other vendors are far more liberal in this regard.
2. I will need to dig deep before upgrading BIOS etc. which is a real shame. I do not aspire to knowing the inner workings of every software framework out there.
3. I might reconsider running on AMD stack. I've been a long-term user but I hate surprises of this nature. Hence my server runs on Xeon rather than AMD equivalent.
Thanks for your quick inputs - much appreciated!
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Posted By: Ray62
Date Posted: 19 Oct 2019 at 3:30am
And just a info regarding the "too new bios" for older CPUs:
I updated my X370 board to the newest bios for using a 3900X, which did not function with the new CPU. But with a 2700X the board is running very well.
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Asrock Fatal1ty X370 Professional Gaming Offline
Under test:
MSI X570_MEG_ACE | AMD Ryzen 9 3900X | Scythe Mugen5 | 2x16GB F4-3200C14D-32GTZ@3466 | ASUS GeForce GTX 1080 Ti FE
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