iM 4,1-14,4 EnableGop: Pre-OpenCore GOP support for EFI-era iMacs and Mac Pros

[Bmju]

Seems not NVRAM, but vBIOS flash chip

That is an NVRAM chip, even though it's not the BIOS NVRAM chip.

 

[Bmju]

@Tratkazir_the_1st - Any success report from yourself yet from the flash to fix Radeon VII bug?

 

[Tratkazir_the_1st]

@Bmju Still thinking... Actually there are 2 Macs with such cards. But I don't want to brick any of them . M.b. at week-end.

 

[Bmju]

@Bmju Still thinking... Actually there are 2 Macs with such cards. But I don't want to brick any of them . M.b. at week-end.

Well, I believe it will just work for you ... but it's your risk so ...

If you want to be really certain you won't brick it, you need to buy a USB CH341A plus SOIC clip, and you need to practice clipping on to the VBIOS flash chip and reading from it, and really, to be sure, writing back to it what you read from it; i.e. practice removing the graphics card and then reading/writing to its flash using a clip and another computer.

Then you will have a backup and you can basically be sure that you have the technology to restore it to its previous state if needed.

But given the other success stories above, the updated VBIOS should just work...

 

[FilthyMuppetInnuendo]

I’d like to add (for the sake of SEO and others looking for the information since it’s not in the OP) and say that EnableGOP works perfectly to make a GTX 980 have a pre-boot screen… from its DVI port (if it has one). DisplayPort ports don’t show a pre-boot screen. I also have an HDMI port on this card, but I have nothing to connect to it so I can’t say if it works.

Further, with this modification, you can’t use the pre-boot screen “blind” anymore (that is, holding Option even when you can’t see it and using the arrow keys and Return to select your boot volume, which is what I did for countless years).