Download atiflash/amdvbflash 2.93
Go here
https://www.techpowerup.com/download/ati-atiflash/
Then look for Version 4.68, underneath 4.68 you will see a link to show older version, click that and you should see version 2.93
Then
Follow these steps carefully:
1. Open your "C:" drive in Windows, create a new folder, call it atiflash.
2. Extract the contents of atiflash_293.zip to the "C:\atiflash" folder
3. Find the bios file you downloaded and rename the bios file to 580nj.rom
4. Move 580nj.rom to the "C:\atiflash" folder
5. Open the start menu, type cmd, when cmd.exe appears right click it and hit "Run as administrator"
6. At the command prompt type in cd\ and press enter until only C:\> is on the screen.
7. Type in cd/atiflash and press enter, you should see C:\atiflash>
7a. At C:\atiflash> type in amdvbflash -i to identify your gpu with 0, 1, 2.
8. At the C:\atiflash> prompt type in
amdvbflash.exe -unlockrom 0 (or 1, 2)
(there is a space between the e and -unlockrom and 0)(0 is the number zero)
press enter and you will be prompted that the "ROM Unlocked"
9. At the C:\atiflash> prompt type in
amdvbflash.exe -f -p 0 580nj.rom (or 1, 2)
(there is a space between the .exe and -f, and a space between -f and -p and 0)press enter.
Follow directions on screen and if flash is successful exit the command prompt and restart, windows should show up on screen
Oh, I forgot to reply, but after a few bricks it and unbricking it I managed to flash the Sapphire rx 570 bios, now UEFI and everything works great, but anyway, thanks
I just posted the latest file for you