LibreELEC shows only its logo when used via my AV receiver

I'm a happy user of LibreELEC for some time. I use it for streaming movies via my AV receiver (Denon AVR-X1000) to my projector (Panasonic PT-AX200E).

I decided to upgrade the hardware from a Raspberry Pi 2 B to an Intel NUC 13. Most of source material was playable with the Raspberry, but I have some material that is unplayable due to its high resolution and required processing power.

I hooked up the NUC to my 4k-monitor and set everything up like before. Works fine. When I connect it to the AV receiver however it can't boot further than to the LibreELEC splash-screen. I didn't set LibreELEC up to only output 4k or something. LibreELEC worked fine in the otherwise same setup running from the Raspberry.

Searching in the forums, I tried troubleshooting via SSH when the problem occurs. I checked dmesg and kodi.log. Both are attached to this post.

Suspicious log-messages perhaps:

2024-04-26 23:20:02.187 T:1340 info <general>: CAESinkALSA::InitializeHW - Your hardware does not support AE_FMT_FLOAT, trying other formats

Any advice how to proceed here?

Thanks a lot,

airflow

Thanks a lot for both your input and ideas.

1) "getedid create" - didn't change anything.

2) set log level 1 and "pastekodi": https://paste.libreelec.tv/related-prawn.log

3) updating to LE12b: i will do it if nothing else helps. First I'd like to try the "easy" ideas, as I'd want to stay on the stable version if possible for stability reasons.

4) moving guisettings.xml to "reset" the config: I can try this. Just two questions about this: 1) can this easily be reverted by copying the file back later? I invested some time in the config and don't want to lose everything 2) will the docker-service continue to run if I do this or will it be erased?

Thanks again for your advice.

All devices are on their latest firmware (speaking of HDMI updates).

I now tried booting with removed guisettings.ml as well. Did not change the behaviour.

Does it make sense to connect it back to the 4k-monitor and manuelly set a fixed resolution of 720p?

Update: I could solve the problem by manually setting the resolution to 1280x720 at 50Hz. Previously it was set to 60Hz. The change in refresh rate did the trick. Merci!