MP 1,1-5,1 Mac Pro 4,1/5,1 (Flashed) help request

[cheapstudent]

Mac Pro flashed from 4.1 to 5.1
working on pixlas mod (completed)
AMD Radeon Pro W7800
Dual CPU Processor Board Tray
2 X5690 CPU (delidded)
96GB HP PC3L-10600R DDR3-1333 RDIMM 647653-081 server memory
Intel AX200 WiFi 6 PCIe BT5.2+WiFi 6
Marvell 88SE9230 PCIe adapter card 4 port for sata lll and 2 port for ESATA RAID controller 6G port
FL1100 USB 3.0 + Type C and front adapter expansion hub PCIe (no power)
Running Ubuntu Server 24.04

Mac Originally ran OS X El Capitan

I mainly need assistance with getting the AMD Radeon Pro W7800 to make the cycle in POST and for the monitor to kick on. I have done quite a bit of reading in articles and use of AI (ChatGPT, Gemini, and Claude) all leading me to a headache. I can successfully log in via with the 05:00.0 NVIDIA GeForce 9500 GT into Ubuntu Server 24.04 and also SSH...

Any thoughts or tips would be greatly appreciated.

 

[tsialex]

Any AMD GPU after the NAVI 1x generation needs to have the GPU firmware patched for it to work with a MacPro5,1 - these GPUs require UEFI HII firmware support and the ancient Apple EFI 1.10 have none.

When any GPU newer than the NAVI 1x generation is installed in a MacPro5,1, the GPU firmware just crashes at power on and you can't complete POST or boot with the Mac Pro.

MacRumors user Syncretic made available patched firmwares for AMD RX 6600/6800/6900, but not for any NAVI 3x, since no macOS support is available for these cards. Read more here. Btw, there is no source of the patches available, so you can't easily adapt it for your GPU and Syncretic is MIA since early 2023.

My suggestion, change the GPU for an older one that works with the Mac Pro.