I dug out one of my boxes. It was already installed with a working LE 11.0 install, but I updated using the latest LE13 image in my test share and the update overwrites/replaces all the boot files, and it rebooted fine afterwards.
The boxes I have are still running the original pre-production boot firmware as I'm not an O2 customer (or in CZ) so the boxes have never been been updated. Yours probably has been, and may also be a newer hardware iteration; although I believe the only change made over time was a different WiFi/BT module, that won't prevent boot, and if Armbian boots the box can boot LE.
You probably need to do a 'toothpick' reset to ensure u-boot searches/finds and loads LE boot scripts from the SD card. These define what boot files to use, and LE uses different files to Armbian.
Boot Log: https://paste.libreelec.tv/great-stallion.log