On my KIII (not pro) I used this image - LibreELEC-S905.arm-8.0-8.0.2a.img and from the tree I used this file - gxbb_p200_2G_1Gbit.dtb.
I used this method to boot:
- Terminal Emulator: boot to Android, insert SD card/USB drive with LE, install Terminal Emulator app (either from Google Play or APKMirror), run it and type reboot update. Your box should reboot to LE.
Everything is working.