This are the graphics settings of a working system
As already stated above: I had these and many other combinations tested.
The only difference I see here is the additional injection of video ports. Haven't used that as I thought using Vervet would define that setting by itself.
@all: Thanks again for your support.
I put these things (again) on my worklist for the weekend, just to make shure not to have left out the one and only working combination that I not yet found.
But I have the feeling that it is not a matter of injecting something for the GPU.
At least not for the operating system, but may be for the initial Clover operation. During that stage something goes wrong and is not corrected later when the OS takes over.
Clover menu wrong resolution, initially dark screen during early OS loading (verbose), but when the desktop is reached (blurry log in window) at least the resolution matches, but only in a small upper left section of the screen...
As it is not possible to make a ioreg readout for the graphics data with this screen limitation, I think I will try to enter the system remotely when it is booted this way.
I'm almost shure that the display data as well as the GPU type and correct framebuffer will show.
Another item on the list for the weekend.