Sapphire RX580 Nitro+ 4gb UEFI/CSM bug

Hi guys!

I have this RX580 from Sapphire that has a bios switch to select between “silence” and “performance” mode. I can use it without issues in silence mode, but when I switch to performance mode I have no video signal for all the boot process, until it comes into Windows 10. It seems to be a similar issue like here: Asus RX 580 UEFI/ CSM Bug

Here’s the bios file that doesn’t show video during the boot:…e_bios.rar?dl=0

Is there any way to fix it? I’m using the GPU on a AsRock Z370 Extreme4 with the latest bios release.

Thanks in advance for the reply!


That bios looks to have been modded to have the same timings for 1500-2000. Card was previously used for mining.

Find a suitable bios


Hi and thanks for the reply!

What do you mean for “same timings for 1500-2000”? Could you explain me better, please?

Also, can you please send me a valid link for the actual flashing method? I’ve already flashed GPUs, but it was at the time of the 5870 ATI, so I don’t know if something has changed.


EDIT: I’ve understand what you mean for “timings for 1500-2000”, looking at the values in PolarisBiosEditor. Is it safe to flash the BIOS you linked?

Ok, I’ve tried to flash the bios on the second link (after taking a look at the difference between mine and the downloaded one) and everything went fine. Now I have signal at boot and so I can enter into bios, too.