URGENT Please!

[LK LAW]

Somebody is picking up my cM today and I can't get my R9 280x to work with the EFI Bootscreen. It runs at PCIe 2.0, boots into recovery and show as R9 280x in macOS High Sierra but I can't get into the boot picker menu!

Please help

 

[ActionableMango]

I know there is R9 280X with BIOS switch--did you accidentally flip the switch to the non-Mac-EFI ROM while prepping the MP for sale?

Did you change cables or monitors and start using a different port, perhaps to one that hasn't been providing boot screens all along?

Also there's also the possibility if you short the correct pins that you can restore to factory flash (to recover from a bad flash). But that is difficult to do on purpose, much less accidentally, so that seems extraordinarily unlikely.

Personally I can't think of any other reason a flashed Mac EFI would spontaneously stop providing boot screens.

 

[LK LAW]

I know there is R9 280X with BIOS switch--did you accidentally flip the switch to the non-Mac-EFI ROM while prepping the MP for sale?

Did you change cables or monitors and start using a different port, perhaps one that hasn't been providing boot screens all along?

Also there's also the possibility if you short the correct pins that you can restore to factory flash (to recover from a bad flash). But that is difficult to do on purpose, much less accidentally, so that seems extraordinarily unlikely.

Personally I can't think of any other reason a flashed Mac EFI would spontaneously stop providing boot screens.

It still shows up in System Report as R9 280x both in PCI info and Graphics/Display

If I flip the Bios Switch on of the BIOSes is indeed the original PC bios.

I tried both the mDP ports and the HDMI

So strange,...

 

[ActionableMango]

Well I'm out of ideas, other than re-flashing it with the same ROM you used last time that originally worked. Obviously the flash is still there since the card is reported correctly, but I can't think of anything else to try, and maybe it got partially corrupt or something.

I'm know I'm grasping at straws here. Perhaps someone more experienced than I will chip in.