By the way, I dug out my sample Odroid C2 and checked the launch of the latest version of Armbian 20.05.4. Recorded to the Android SD card. Added lines to (boot.ini), wrote Armbian to a USB flash drive, and configured (uEnv.txt). Everything starts normally from USB and you can configure the system without ssh. In the same mode, I checked the launch of Libreelec from USB, everything works. I don't have eMMC for C2, so I can't test working with SD+eMMC.