I've been searching all day long...
I have Rpi3B, monitor able max 1280x1024, connected with HDMI to DVI cable.
After I did upgrade from 10.0.4 to 10.95.1 or 11.0.0 I get black screen. No logo of libreelec, monitor woke up from standby with black screen, after there is kodi starting monitor goes to sleep again.
Kodi starts (I have sound connected separately from HDMI, I can connect to tvheadend, streaming works, ssh works, samba works...
Tried switch to projector with FullHD - no change.
Tried edit cmdline.txt with video=HDMI-A-1:1280x1024M@60D, tried also lower resolutions, tried edit whitelist in guisettings.xml, no change. In 10.0.4 everything worked.
I also tried new installation of 11.0.0 on clean SD card, same results...