I saw a major kernel change in LibreELEC-RPi4.arm-10.0-nightly-20210724-0b9677f.tar, going to aarch64. Is it including More vc4 fixes by mripard · Pull Request #4470 · raspberrypi/linux · GitHub, supposed to fix RPi4/kms: boot hangs if two monitors are connected · Issue #4465 · raspberrypi/linux · GitHub ?
I could try, but I have to admit that I'm not looking forward breaking and restoring from backup the lounge system on a Saturday evening! That would no do much good to my WAF...
I tried that, it wont boot, so now its a complete reinstall... and it will be a while before i try that again.