By design, the Mac Pro EFI BootROM uses UGA (an older standard) for screen output. Mac-compatible cards provide UGA, which lets you see the native boot picker and the early boot screens (before MacOS loads). Without a UGA-compatible card (i.e. with non-Mac/PC cards), you'll see a black screen until something loads a driver that can speak to your video card - that's typically either OpenCore or MacOS itself. OpenCore loads early enough that the native screens aren't really necessary. As I understand it (I've never looked at an MVC card), MVC patches their cards to include UGA support, so you can use the native boot picker and see the boot screens immediately, without the need for OpenCore. (And, in the case of the RX6x00 cards, they've presumably fixed the same AMD bug that my patch fixes.)
Unfortunately, yes. As
@tsialex correctly points out, you can't boot a cMP with an unpatched RX6x00 card in it; the card's initialization code contains a bug that prevents booting (fixing that is the whole point of my patch!). So, if you're using software flashing, you'll need to do that on a non-Mac PC.
To simplify things, I've attached a Windows version of the FixRX6x00 patcher program. It's still a command-line program (no GUI), same instructions as the MacOS version in my
previous post. At least this way, there's less shuffling back and forth between systems.
Your Python script has a problem. It complains about the EFI ROM not being the last image, but that's not a requirement for EFI option ROMs. In this case, the x86_64 EFI code appears before the ARM64 EFI code - but in the output from your script, the ARM64 code gets removed. Also, while I don't have an RX6900XT to test with, I can state that GOP is most definitely provided by the card's original ROM.
Correct. As I said in my original post,
@caingraywood was using a hardware flasher (I think he said it was an RT809F). I don't know his methodology - he may have been flashing
in situ, or he may have been physically replacing the chips. In any case, he wasn't using software flashing. Since a cMP can't even POST with an unpatched RX6x00 card, it's necessary to flash it using either a PC (Windows/Linux) or a hardware flasher (or, I suppose, a MP7,1?).
To help simplify things, I pulled all of the RX6600/6600XT/6800/6800XT/6900XT ROMs from TechPowerup, patched them, and have attached them to this post.
However, be advised that patching the ROM that came with your particular card will almost always be the better choice. Use the attached ROM images at your own risk. If you choose to use one of the attached ROM images, verify that the make/model and version number matches your card.
