You shouldn't need to use a hex editor to change the device-id of the GPU. You should only need to re-flash the GPU with the option `-padevid=<ID>` in the command. Make sure to check the help command for ATIFlash.
Example:
Code:
AtiFlash.exe -f -pa -padevid=73bf 0 newenhancedbios.rom
I believe you may have confused what these arguments do here.
According to the help text, invoking atiflash with -pa and -padevid governs which devices the VBIOS is written
to.
It does not, however, modify anything about the card itself, as these arguments are simply selectors so you can more easily target which devices you want to flash.
To modify anything inside the VBIOS, you will still need to hex-edit it (or use a GUI editor provided some kind soul has already reverse-engineered the various settings).
Invoking this with an XTXH card in the system will not flash anything, because -padevid=73bf targets cards with a different ID (specifically, the "normal" 6900 XT's). If anything, it should be set to 73af, which will actually target the correct card.
Unfortunately however, ATIFlash 3.15 is the latest version that is currently available. It is also the case that 3.15 does not support the XTXH cards yet, only the regular 6900 XT and its smaller brethren. As such, even though I already have the modified VBIOS, I am currently unable to flash it.
This is also partially due to the fact that none of the public versions of ATIFlash provide the "-f" flag (which forces flashing even if the card is unknown). Unless somebody here has access to a version of ATIFlash with this flag and is willing to share it with me, this is as far as I can go for the time being.
As soon as a new version of ATIFlash becomes available, I'll try the VBIOS mod.
EDIT: It appears that the linux version of this tool *may* allow force flashing but the Windows version doesn't. Alas, it seems the Linux version hasn't been updated since August 2019, so I'm not sure whether this actually supports the new cards at all.
I will set up a Linux Live USB and I'll give that a shot next.