[Success] Radeon RX 6800 XT - Big Sur

[byteminer]

Because NAVI 21 device IDs appear in multiple kexts, I wonder if we need to add 0x73AF to some or all of them:

• AMDRadeonX6000Framebuffer.kext
• AMDRadeonX6800HWLibs.kext
• AMDRadeonX6000.kext (for NAVI 21 Graphics Accelerator)

The attached kext combines Navi 21 IOKit Personalities from the two boldfaced items.

Unfortunately no change again.

 

[dehjomz]

Unfortunately no change again.

You may have done this already but have you tried booting (using the updated ssdts)with just the Big navi card alone, and remove the 580?

 

[byteminer]

You may have done this already but have you tried booting (using the updated ssdts)with just the Big navi card alone, and remove the 580?

Yeah, I've tried that a few times along the way.
In the cases where the device-id spoofing does not work, I can boot into macOS, but with a generic framebuffer attached. The GPU still shows up the same as with the RX580 in the system, though.

In the one case where spoofing the ID via SSDT only leads to the black-screen boot, booting off of the Big Navi card directly gives me a freeze frame at the end of the boot process, just before entering the login screen. I assume the last picture only remains because macOS loses its handle on the GPU at that point.

 

[CaseySJ]

Yeah, I've tried that a few times along the way.
In the cases where the device-id spoofing does not work, I can boot into macOS, but with a generic framebuffer attached. The GPU still shows up the same as with the RX580 in the system, though.

In the one case where spoofing the ID via SSDT only leads to the black-screen boot, booting off of the Big Navi card directly gives me a freeze frame at the end of the boot process, just before entering the login screen. I assume the last picture only remains because macOS loses its handle on the GPU at that point.

** Mission Irresponsible: I disavow all knowledge of this post **

Crypto miners regularly modify the VBIOS on their AMD GPUs using ATI Flash. The latest version from TechPowerUp supports NAVI 21. This is used to read/write the VBIOS, but another tool called Radeon BIOS Editor or RBE is used to modify the BIOS. Both are only usable in Windows.

 

[RobyRew]

finally got it working. did took a long cut of downloading and installing the recovery of CATALINE 10.5.7 and then updating via beta profile. but its here, finally.

People should remember to leave their system do the work if they have not added the BOOT ARGS: "agdpmod=pikera" the installation happens on its own. when you don't see the mac Installation and only see mac as boot option in the open core menu, you know that its good to go. now you can either add the option and you will start getting the display as mentioned before.

The only issue I have is that I find the brigthness low even after 100 % at hardware level. what can the be issue here ?

View attachment 516228

If this is real, can you enlighten us a bit?
I think you would be the first one I see that has the new 6X00 running with Hardware Acceleration

 

[TheBloke]

If this is real, can you enlighten us a bit?
I think you would be the first one I see that has the new 6X00 running with Hardware Acceleration

Have you missed everything said in the last 20+ pages? 6800/6800XT/6900XT drivers have been out for days, in 11.4 beta 1.

 

[byteminer]

** Mission Irresponsible: I disavow all knowledge of this post **

Crypto miners regularly modify the VBIOS on their AMD GPUs using ATI Flash. The latest version from TechPowerUp supports NAVI 21. This is used to read/write the VBIOS, but another tool called Radeon BIOS Editor or RBE is used to modify the BIOS. Both are only usable in Windows.

Well, I might give that a shot, I was about to install Windows for dual booting anyway.
I'll update you guys if I either succeed or blow up, but it'll probably take me a few days to set this up.

 

[CaseySJ]

Well, I might give that a shot, I was about to install Windows for dual booting anyway.
I'll update you guys if I either succeed or blow up, but it'll probably take me a few days to set this up.

Ouch, it seems Radeon BIOS Editor (RBE) does not support the latest AMD GPUs.

---

 

[byteminer]

Luckily IgorsLab Red BIOS Editor (which funnily enough carries the same acronym) does, at least in part.
I'll be messing around with their toolset for now, see how far I can get.

 

[TheBloke]

I did wonder if he could maybe just download a reference MBA VBIOS and flash that?

Though I don't know what's different about these binned cards - whether they have other BIOS tweaks and improvements that might be lost at the same time?