I've found another post on this forum where a user had a black screen but after the installation. Might not be related to our problem but it is worth a try.
XLNC suggested in that topic that one should try run the installer with these bootflags:
viewtopic.php?f=52&t=3814&p=36927&hilit ... 870#p36927
You can change the bootflags in Clover bootloader when you boot from USB in the menu before clicking "Boot MacOSInstaller", there is an Option menu.
P.S. I've had a much bigger problem appear too, after letting the black screen be for a while, my computer went into sleep after some time and afterwards did not POST anymore. Couldn't even get to Windows. Had to clear CMOS by adjusting the jumpers on the motherboard so be careful.
EDIT: I think those bootflags above are connected with Radeon GPU behavior. I think this problem has to do something with AMD GPUs? Not sure. However, it is worth a try no matter what configuration you have, and post your results.
UPDATE: I tried several things and had no success... However I will post my methods here so you can try them out too.
So I tried:
- reppluging the video cable
- unplugging the second monitor cable
- flag -lilubetaall and radpg=15 combined
- flag radpg=15 alone
- flag -radvesa alone
- changed flag npci=0x2000 to npci=0x3000 and added flag PCIRootUID=0 (combined)
When I played with bootflags I only added new ones or modified the existing ones, I never removed ones that were there by default.