I recommend getting the official RPi power supply
This is known to work reliably, phone/tablet chargers are in general hit and miss.
so long,
Hias
Jul 20 04:12:23.794283 LibreELEC kernel: hwmon hwmon0: Undervoltage detected!Use a proper power supply.
so long,
Hias
Thanks a lot for reporting back!
I'll add the changes to LE 11.0.4 (11.0.3 is already on the way being uploaded to mirror sites), until then just use this image (it's basically LE 11.0.3 plus the POE hat change).
so long,
Hias
Thanks for the report!
gpio-fan was enabled, but pwm-fan (which is needed for the POE hat) was missing.
Could you please test and report back if this build works fine (just copy the tar file to the update share and reboot)? It includes the pwm-fan module
https://www.horus.com/~hias/tmp/libreelec/LibreELEC-RPi4.arm-11.0-devel-20230718205708-aab3824.tar
so long,
Hias
If you came from LE9 you probably missed the LE10 release notes
LibreELEC (Matrix) 10.0.4 - LibreELEC
Hyperion no longer works due to changes in the video pipeline. Consider hardare/external grabbers.
This hasn't changed since then.
so long,
Hias
ssh in and run "getedid create"
so long,
Hias
RPi4 doesn't support 1366x768 so in general it'll use 720p instead (which usually works fine).
See also https://forums.raspberrypi.com/viewtopic.php?t=284865
so long,
Hias
Thanks, the log looks fine to me though, RPi4 is outputting 1280x720p60.
It might be worth testing with a direct connection from RPi to the TV (taking the AVR out of the chain) and also using a different HDMI cable - all of that could cause issues.
Oh and if you are using a case (esp an Argon One) try without it. Argon cases have a long history of causing HDMI issues and personally I had an issue with another case because the micro HDMI connector couldn't be fully inserted with it (thus causing intermittent contact problems).
so long,
Hias
Remove "avoid_warnings=1" from config.txt and post another log.
If you added it to get rid of "low voltage" warnings then get a better power supply - insufficient power will cause all sorts of issues, especially the one you mentioned.
so long,
Hias
Ah, if you expect NTFS features and performance then ext4 is not for you. unfortunately ext4 is a lot faster than NTFS 
so long,
Hias
Format the drive(s) with ext4 - this one works best in LE
so long,
Hias
Test with just the TV hat installed, if you have another (audio) hat installed, it'll easy to create a clash (eg on the HAT EEPROM / autodetect pins) and something won't work.
Bent pins, damaged header or TV hat hardware are all possibilities - and from the linked threads it seemed replacing the HAT solved the issues.
If you have a RPi2/3/4 you just need to plug in the TV hat, no need for soldering, and it will just work, both on LE and RPiOS.
so long,
Hias
This sounds a lot like you have a connection issue, a hardware problem or some configuration issue, especially as it's also failing on RPi OS.
I did a quick test on RPi4 with latest LE12 build and it detected the TV hat just fine - without adding anything to config.txt (it's plug-and-play)
LibreELEC:~ # dmesg | grep -i cx
[ 14.786410] dvbdev: DVB: registering new adapter (CXD2880)
[ 14.834939] cxd2880: cxd2880_attach: CXD2880 driver version: Ver 1.4.1 - 1.0.5
[ 14.834957] cxd2880 spi0.0: DVB: registering adapter 0 frontend 0 (Sony CXD2880)...
[ 14.835403] cxd2880_spi: cxd2880_spi_probe: Sony CXD2880 has successfully attached.so long,
Hias
LE12 on RPi4 switched from 32bit to 64bit builds, and when trying to update from LE11 to LE12 you'll get an error message shown on screen because the compatibility check failed.
You can disable the check by creating a .nocompat file in the .update folder
touch /storage/.update/.nocompatNote though that you could run into issues with addons because of the 32->64bit switch (updating them should fix this).
Also note that switching back from LE12 to LE11 is not supported.
so long,
Hias
I'd recommend using either LE11 official or LE11 nightly builds.
LE11 updates are very conservative, mainly bugfixes, and LE11 nightlies have a low risk of breaking stuff (but might contain fixes you'd like to have since the latest official release).
LE12 is OTOH is rather experimental, gets regular major updates which could break stuff and uses kodi Omega alpha versions. Only use that if you are prepared to fix stuff yourself when something breaks.
so long,
Hias
A good, fast SD card is certainly a key point in getting good performance on RPi (and all other SBCs that use SD as storage). Random write speed is also important, especially if you use PVR which regularly updates the EPG database.
Personally I use Sandisk Extreme Pro 32GB micro SD cards and I'm quite satisfied with overall performance on RPi.
Another point is to stay away from "heavy" skins. The stock Estuary skin and eg Confluence are fine but others that use tons of effects, lot of huge textures etc won't be fun on RPi - it's GPU isn't exactly high end.
If you already have the RPi I'd also recommend to just invest the ~10 bucks for a good SD card, make sure you have a quality HDMI cable (the official RPi one will be fine for 4kp60) and give it a try,
My recommendation would be to use the latest LE11 nightly build as it contains a couple of important fixes since the latest official LE11 release. Get it from here:
https://test.libreelec.tv/11.0/RPi/RPi4/
so long,
Hias
Power up the RPi with the TV switched on, ssh in, run getedid create and reboot.
so long,
Hias
ApexDE the fix is now in LE11 nightlies.
Could you please update to the latest build (currently https://test.libreelec.tv/11.0/RPi/RPi4/…-a54b88f.img.gz)?
It includes an additional ffmpeg fix for crashes with certain H264 files/streams - better use that until the next LE11 release is out.
so long,
Hias