[RPi4] No video output on HDMI0 (anmore)

    Hello Everyone :)

    So, up until a while ago everything worked great. My setup is the following:
    Raspberry Pi 4b (4GB RAM) outputting to HDMI0 (the port next to the USB-C) into a HDMI 2.1 Switch that Feeds a HDMI 2.1 Splitter from which one output goes to the TV (Hisense 55E7NQ, 2024) and the other one into an HDMI grabber that goes into HyperHDR (also running on the Pi). I remember when I first set it up I had some problems to get a picture out of the Pi but then it worked and I had no issues over the past months until about a week ago when I reinstalled LibreElec due to some plugin problems.

    I can't get any image out of the HDMI0 port. The TV recognizes that Kodi is indeed connected there (in the HDMI menu) but tells me "weak or no HDMI Signal". I tried restarting everything multiple times, changed the startup order but to no avail. Switching to HDMI1 on the Pi and rebooting immediately fixes the issue and I had picture again with the setup (but no HDMI CEC and from what I read it's very tricky to get that working). If I remove the HDMI Switch and plug the Pi straight into the splitter, the first HDMI port works as expected. Weird thing is, my PC feeding the same HDMI switch before the splitter has no issues at all and I even bought a different HDMI 2.1 switch yesterday (one that has its own power supply, just to be sure) but the exact same behavior occurred. No output from the first port, second one and PC work flawlessly.
    While trying to get this working, I had image for a short while but when I restarted everything the problem reappeared and now I can't reproduce it.

    Any Idea what could be the problem? I don't think the port can be physically defective since there's no problems when it's connected to the splitter directly, even when I move the cable around.. Thanks for your help!

    Depends on how your HDMI switch works. The modern approach should utilize CEC routing information. This will work only if the HDMI source (KODI) is configured and behaves right. As there were many bugs within libCEC and KODI as well, I recommend to skip LE 12.2.x if you are depend on working CEC. Please try with an LE 13 nightly image of 2026-05-14 and upwards and prevent usage of 'getedid create' as the static EDID information disturbs the CEC negotiation in my experience.

    With my RPi4 setup this parameter added to kernel boot line cmdline.txt was required to get a working HDMI0 output with 12.2.x.

    Code
    video=HDMI-A-1:1920x1080M@60D

    But with LE13 nightly 2026-04-20 upwards, this line prevented CEC from working right and should removed!

    PS: I haven't tested this myself, but with a current LE13 nightly build, CEC should also work on HDMI1. But HDMI0 remains the recommended port as the optimized GPU capabilities (RPi4 resources/firmware limitation).