Unstable HDMI signal

[MichaelRu]

I swapped cables and connections at the receiver, disabled CEC, tried various configurations in config.txt, but nothing worked. Things I set in config.txt seem to only be used until the Kodi UI is started. Even on Raspbian I did get the problems I mentioned, but not as fast as in Kodi. I needed to wait about 15mins. The worst was LibreElec where the HDMI signal was lost every few seconds.

I played with it for days but eventually gave up. Now I bought a Fire TV, connected that with the same cable to the same input connection on the receiver and it works like a charm.

Thanks for your help nevertheless.