Just an FYI, and kudos to the CoreELEC group.
I have a HK1 RBOX X4 that uses the Amlogic S905X4, so thought I would give this a try. Bingo, it installs and plays perfectly.
I used a 64Gbit microSD card, and used Etcher to burn this version CoreELEC-Amlogic-ng.arm-19.5-Matrix_nightly_20220528-Generic.img.gz to the card. Then I used this DTB cs2_s905x4_ dtb.
I inserted the microSD card into my box, remove the power plug, then used a toothpick to depress the reset button inside the AV port. While depressing the reset button, I applied power, and bingo the CoreELEC logo popped up right away…
I installed the Kodi Backup addon then did a restore of one of my backups from another device (a little over 6gigs of data).
Ethernet and WIFI work, but the stock IR remote does NOT work, but that was expected. Also, the option to boot to emmc is missing, so have to remove the SD card to get back into the Android OS.
Still testing… Great job from the CoreELEC team getting this OS to run on the X4 devices.