I purchased a 2nd hand card on ebay and at first it gave error 43 on Windows 10. The app amdtkdag-patcher did the job to successfully recognise and install the card.
However, error 43 is surely due to a tampered vBIOS. The bad news is that previous owner flashed it on 'legacy' switch mode, and my motherboard does not have UEFI mode (can boot up UEFI firmwares as Windows 10 Bootloader or GRUB, but it does not have a UEFI BIOS).
So I need an original Sapphire RX 480 4GB OC Edition BIOS (legacy) to set up all back to normal. I have experienced random shutdowns when load is 100% during a long period of time.
I attach a snapshot of GPU-z. Card can be identified by DEVID, SSID, VSID and already flashed (working) BIOS.
Sorry, I flashed that vBIOS with the legacy switch set to CSM, and it bricked. I got it working again by halting PC execution after POST with PSU cables removed from the GPU, connecting the cables during GRUB, and letting Linux recognise the card, and then reflash the backup vBIOS that came shipped (the one giving error 43).
Are you sure that those vBIOS hosted at techpowerups are CSM ones?
I need a factory CSM vBIOS for my GPU. My Motherboard does not have UEFI BIOS, so it can not boot in UEFI mode, at least with the case closed and without the procedure I mentioned.