AMD : BSOD unsupported processor since Windows build 26100.4202+ ( update kb5060842 + its preview kb5058499 )

[KciNicK]

After repeatedly rebooting due to an "unsupported processor error," you can start the computer by performing "Startup Repair" in the recovery console that is started. (The computer will transition to Windows setup.)
KB5063060 (or KB5060842) will cause an installation error, but it will not be reinstalled.

In the recovery screen, you will need to install the virtio driver from the command prompt.

drvload D:\vioscsi\w11\amd64\vioscsi.inf

well, of course not installing the update will fix the problem, the thing is, those are cumulative updates, that means, no more updates

 

[masato]

The following settings resolved the "Unsupported Processor" issue:

args: -cpu 'host,arch_capabilities=off'

The following flags seem to be set when the CPU is host.
They were not present when using EPYC-v4 or physical installation.

 

[Nick Kooij]

The following settings resolved the "Unsupported Processor" issue:

args: -cpu 'host,arch_capabilities=off'

The following flags seem to be set when the CPU is host.
They were not present when using EPYC-v4 or physical installation.

Nice. That worked for me too.

Although I'm using the following custom cpu model rather than the args parameter:

cpu-model: host-fix
    flags -arch-capabilities
    reported-model host

 

[_gabriel]

args: -cpu 'host,arch_capabilities=off'

Thanks, works here.