Sonoma works, Windows has GPU issues when picked in OpenCore

[renox92]

I have a single drive multiboot setup with Sonoma and Windows 11. I can boot just fine into Sonoma via OC, and into Windows using Windows boot manager. However, if I pick Windows in OC, I get black screen. I get the Windows chime, so it technically boots, but I can't do anything.
I do have Microsoft folder inside EFI one. I also tried setting CustomSMBIOSGuid to True, and adding CutomSMBIOSMode=Custom, with no result.

After some testing with a dual monitor setup where 1 monitor connects to iGPU and another to dGPU (needed for OpenCore) here are the results:

• Booting via OpenCore: dGPU monitor shows OpenCore, after picking Windows it goes black, but iGPU monitor starts working. Looking into Device manager, and inside properties for RX 6600 XT I get "Windows has stopped this device" with error 43.
• Booting via Windows boot manager (same monitor to GPU connections): now BOTH iGPU and dGPU monitors work, Device manager shows no errors.

I don't get how using OpenCore to pick Windows somehow breaks drivers(?) or whatever for GPU.

Just tried using old EFI folder from iGPU hackintosh that I couldn't get working with dGPU and it boots in Windows fine as well. Gonna try and change differences in these two configs one by one, but maybe someone can tell what's causing this?

 

[renox92]

Gonna try and change differences in these two configs one by one

Luckily found the problem on the 4th step. I saw this a few times here while I was searching for probable cause of the issue, but yeah "ResizeGpuBars" should always be -1. Since I was trying to enable it I set both ResizeGpuBars and ResizeAppleGpuBars to 0.