I wanted to flash a different BIOS on my Sapphire RX 7900 XTX Nitro+, specifically a BIOS from Benik3. Unfortunately, I managed to kill both BIOS chips.

AMDVBFlash modded thread:
https://www.overclock.net/threads/amdvbflash-modded.1817620/

Since I had never worked with a CH341A programmer before, I looked for someone who actually knew what they were doing. That’s how I ended up at CCC_Wi / Chaos Computer Club Wiesbaden.

They helped me a lot. Special thanks to X41 – he supported me massively through the whole process. We managed to recover at least one of the two BIOS chips. Luckily, I had created a backup.rom dump before doing anything with the BIOS.

The recovery process honestly felt like open-heart surgery – see the pictures. After that, I was just happy that the card was alive again.

Yesterday, I tried to recover the second BIOS as well.

Warning: Switching the BIOS selector while the card is powered on is risky. This is not a recommendation, just what worked in my case.

With the help of ChatGPT and some research, I found out that if you are booted from, for example, BIOS 1, and that BIOS works fine with Windows fully booted, you can switch the physical BIOS switch to the broken BIOS 2 while the system is still running. After that, you can try flashing the broken BIOS again.

That is exactly what I did, and it worked on the second attempt.

I got the new BIOS files from here:
https://drive.google.com/file/d/1iByApA8rB7wK__Mn8EArCVW0uAZQk3hy/view

Important note:

In my case, the original flashing issue was probably caused by Windows and the file extension. Because of the dot in the filename, Windows recognized both files as .s59, which makes no sense for this use case. They should have been recognized as .rom files.

After renaming the files correctly, AMDVBFlash was able to read the BIOS file properly.

My strong recommendation: Before flashing anything, first check whether AMDVBFlash can actually read the BIOS file.

Useful commands:

amdvbflash -i

Shows BIOS information.

amdvbflash -biosfileinfo bios.rom

Checks the BIOS file without flashing it.

amdvbflash -s 0 backup.rom

Creates a backup of the current BIOS. Do this before every flash attempt.

For flashing RDNA 3 / RDNA 4, I would recommend using a suitable modded version of AMDVBFlash and flashing only with -fp, for example:

amdvbflash -p 0 newbios.rom -fp

Again, huge thanks to CCC Wiesbaden and especially X41. Without their help, the card would probably still be dead.

Maybe this helps someone else who also bricked their Sapphire RX 7900 XTX Nitro+.