@EmilB As long you is having the original u-bootloader on the internal eMMC the device cant boot armbian on external storage.
Erasing the eMMC is making the internal ROM in the SOC looking for u-bootloader on the SD-card and you can then booting SD, USB and internal storage from it if doing the config OK.
My box was not liking the standard bootloader but i was getting it working then finding one working one and flashing it from MASKROM mode on the eMMC and then i can booting from all connected device also USB if the internal not being OK and can fixing it from CLI.
