Boot hangs with IGPU framebuffer patch

[skolby]

I am attempting to enable the IGPU in Catalina in preparation for replacing my GTX 980 Ti with a newer NVIDIA card. For the time being the 980 Ti is still in PCI slot 1 for when I boot into my working High Sierra install or Windows. I have tried each of the device IDs for Skylake listed on the WhateverGreen framebuffer guide using the boot argument igfxframe=0x19120000. All except for the headless device IDs stop at this line on boot:

IOConsoleUsers: gIOScreenLockState 3, hs 0, bs 0, now 0, sm 0x0

With a headless device ID I can boot into Catalina without hardware acceleration using the monitor connected to the 980 Ti.

Here's what I have configured:

• Clean install of Catalina 10.15.3, updated to 10.15.7, on a separate SSD
• Clover 5122
• New EFI partition for Catalina
• New config.plist
• Latest Lilu and WhateverGreen are in EFI/Clover/kexts/Other
• IGPU connected to monitor with mini DP out
• BIOS:

• Initial display output: PCI 1 (black screen after hitting the line above when using IGFX)
• DVMT memory allocation: 64MB
• DVMT total memory size: Max

I've also tried with the -wegnoegpu argument but that did that make any difference. Can anyone help me solve this problem? My config.plist, kexts, and log screenshot are attached.

 

[skolby]

Update:

I got the IGPU and 980 Ti working in High Sierra by setting the IGPU as default in the BIOS, and using platform-id 0x19120000 and device-id 0x1912. However, the same settings in Catalina result in a black screen on the IGPU on boot (and no signal to the 980 Ti). I tried with and without -wegnoegpu with the same result. Can anyone tell me why this doesn't work in Catalina?