I have tried, unsuccessfully. I admit that due to my low qualifications
Hi, this dialog touches on a point where unsupported macs config is crossing over with hackintosh config....
(tl;dr jump towards end)
I've been coming at the forums as resources from both perspectives, so this caught my eye. Esp, wrt OpenCore which in my view is becoming the defacto framework for applying patches. For hackintosh there's potentially interesting work going on to build an automator for OpenCore config that will allow users to organize golden configs. It's too soon to tell how this will go, but you could have a point of view where Apple Macs are themselves regarded as golden builds, in terms of OC config mgmt.
The key is OpenCore layout of EFI folder. And it's also in the amazing resource of the Dortania OpenCore Guide, which I suggest everyone here can benefit from at least an awareness. But I mention this just as an aside.
In this case of troubleshooting the external black-screen, this is a common problem with hackintosh config, trying to get various combos of on-board intel vs discreet AMD / Nvidia graphics to work, including VDA (Intel Quicksync) to work for efficient graphics.
The agpmod=vit9696 patch suggestion is one of several Whatevergreen.kext (graphics patch manager) options for overriding board-ids so macOS doesn't punt on graphics output on unsupported configs.
OK, so given the above context as a bacground, I'll get to your issue at hand, switching to OCLP and lost graphics output:
When you write you were "unsuccessful" fo you mean unsuccessful in the sense that the suggestion to add the agpmod=vit9696 device property didn't help your setup? Or in the sense that you weren't able to add the option because of unfamiliarity with applying OC patches?
I'll assume the latter, just to avoid an exchange and because maybe the details will be useful to others playing with OCLP. Here, due to the way you are applying patches, you may have a case where your point of view on unsupported Mac config might as well be POV of troubleshooting a hackintosh based on OpenCore.
tl;dr:
The agpmod=vit9696 patch referenced by
@Ausdauersportler was provided in the context of OpenCore config.plist option to Whatevergreen.kext, either by adding a boot-arg, or adding a DeviceProperty for the graphics ACPI device node (my jargon might be a little goofy here 'cause various vernaculars are getting smashed together: OC, ACPI, Windows, etc).
So to add the patch option, you will edit your OCLP EFI config.plist and add the option on of these two ways. Typically the boot-arg option is used when trouble-shooting, and the DeviceProperties option is used to cement working config. Boot args can be applied in the EFI shell to speed trouble-shooting, but there may sometimes implications with NVRAM persistence, so the shell is for the canny troubleshooter — with great power comes great responsibility, something something stan lee / peter parker.
So if you want to learn more about this, the Dortania OpenCore Guide is the place to go. Just search the googlez.
P. S.
IMO the strengths of the OC approach should have a lasting positive effect on approaching config for "unsupported macs", which means that looking at it from hackintosh perspective will be time well-spent. The cool aspect of OC is that it demystifies UEFI, and what you learn can in the long run cross over better understanding of Linux and Windows too.
So you are on a good path by playing with OCLP.
forums.macrumors.com
There might be even graphics acceleration patches available for the HD3000, again, go to the first post and check download link of OCLP and the docs on this GitHub page.
