I updated the BIOS (see https://www.asrock.com/MB/AMD/B550%2...index.asp#BIOS) from 1.20 to 1.90, hoping that this might fix the issue. Actually, after the update I longer get the error messages about IRQ, so that's at least nice. Still, the computer won't boot however.

I will try contacting ASRock, but seeing as my NVMe SSD isn't actually supported according to their list (https://www.asrock.com/mb/AMD/B550%2...ex.asp#Storage) I suspect I will not be able to get much help. I'm considering buying an M.2 NVMe to USB adapter in order to further examine the SSD, and possiby rescue some files which I had not backed up. I will probably also buy a supported NVMe SSD for my motherboard and see if that will work.

Unfortunately, I don't have so much time to try the above things right now, but I will make an update at some later stage. Hence I leave the thread as unsolved for now. Thanks for all the help so far!

Hi again!

Sorry for taking so long to update the thread.

I have now acquired an M.2 NVMe to USB adapter, in order to check the integrity of my SSD. Using this adapter, I have no trouble accessing files e.g. in my home folder on the SSD, when I access the drive through the USB-adapter. Are there any checks I can do, with the SSD mounted through the USB-adapter, to further check the integrity of the drive?