Tanix TX6 is H6 based Android TV Box and it can boot from SD cards prepared with PhoenixCard. It should be possible to make it work with Armbian too, right? I tried a recent Lite2 image, it didn't work, but it also didn't boot main Android, which means SD boot takes priority. I don't think it's a normal behavior for other Android TV boxes, but maybe it is for those with H6 boards.