Only an Amlogic SDIO debug board would be an alternative to the physical UART port, but it also requires a TTL adapter.
Round #3: http://libreelec.dtech.hu/snapshots/20220504/
If the tuner doesn't work with this either, I really have no further idea without the system log.
Neither my friend. I wonder if it is due to crazycats tuner driver. I saw other img. that have it, but this doesn´t