Thanks for responding, but it doesn’t work for me. When I selected PCM audio and set the channels to 7.1, the default passthrough device (greyed out) was still the HDMI audio device. I tried with passthrough set (I know this is not relevant for LPCM, but my AV amp is capable of all Dolby/DTS variants) and with passthrough switched off. Either way 2.0 audio is perfect at all resolutions but multichannel (5.0 or 5.1) audio is silent. Debug log etc. is at ix.io/2s4p if anyone cares to take a look.
I’m running from micro-SD card but I do have an older LibreELEC installed on my internal flash (it’s kzaqs build).