I loaded Libreelec 9.2.0 on my Raspberry PI 4 4GB and connected hdmi 0 to my Yamaha AV receiver. An Optoma projector is connected to the avr, but the receiver is searching for a video signal all the time, but I can hear the Kodi menu. The problem is the same with raspbian and I tried various options like hdmi safe=1, ignore edid, etc., but it didn't help.
The cable is working fine, because when I connect it to my LG monitor I have no problems at all.
The only thing which helped a little was disabling dtoverlay=vc4-fkms-v3d, then raspbian did work, but Kodi didn't and Libreelec at least showed the splash screen.
Please help!