Hi,
I tried Orange Pi One Plus H6 version of LibreElec from here: https://test.libreelec.tv, sound is working through HDMI, also detects resolution with HDMI-VGA converter and in both cases i have sound and hardware accelerated graphics, youtube at full fps with audio sync.
I disabled 2 cores with
echo 0 | sudo tee /sys/devices/system/cpu/cpu2/online
echo 0 | sudo tee /sys/devices/system/cpu/cpu3/online
and works perfect without heatsink.
But sadly this is not what I want, I need X11 with hardware acceleration and chrome browser, I tes