I have another problem which is not a bug, so probably its place is here.

Friendly Elec offers a very useful eflasher utility, with a one click backup. This utility requires that the system starts on the SD card, and the emmc is available. Unfortunately, due to the slightly strange way boot order is handled on this machine, this seems no longer possible.

https://wiki.friendlyelec.com/wiki/index.php/NanoPi_R5S#The_Boot_order_between_eMMC_and_SD_card

As far as I understand, when Armbian is loaded on the eMMC, we are in the situation where the eMMC has an Image with Mainline U-boot. And in this case, whatever is present on the SD card, boot is always done on the eMMC.

Method 1 does not give any result, because the file created is trashed on reboot.

Method 2 (MaskROM) masks the eMMC, which makes impossible the backup of the eMMC, or the loading of a new image, with this utility.

If I understand well the table, the only way to overcome this problem would be to make the image recognized as a FriendlyElec image. I have no idea if it is possible and how.