KM8P: Recovery Boot Loop ("No command")

I wanted to install Balbes' Armbian image on Mecool KM8P but failed miserably: At first it took me weeks to get my KM8Ps into recovery mode, only to realize that the better/best
installation procedure is via the stock Android update routine.
Unfortunately I now have 3 KM8P showing the same behaviour: They always boot into the recovery mode, showing the defunct Android with the "No command" message.
I can't get out of the recovery mode back into Android to do a "normal" installation via the update routine. And I can't figure out how to install @balbes150 images from
the recovery mode. And I can't boot directly into an image (I guess due to this U-Boot problem with 5.x kernels). And I can't try and install another Android image from
Recovery because the only KM8P Android firmware image I was able to find is older than the installed Android (dated Nov 2017), so this doesn't work either.

I managed to install Armbian on a M8S pro the other day, but with the KM8Ps I'm stuck
Any help or pointers to help would really be appreciated!

I'm currently using Armbian_20.05.4_Arm-64_focal_current_5.7.0-rc6_20200519.img or Armbian_20.05.4_Arm-64_bionic_current_5.7.0-rc6_20200519.img.

Thanks

Edited May 21, 20206 yr by n00b