Wow. I’m glad I found this thread if for no other reason than misery loves company!
I’m having this same issue of armbian running fine off an SD card, but not booting from the emmc. I get an error that the uuid isn’t responding.
I’ve tried to install to emmc from dd, nand-sata-install, and even flashing the armbian image directly onto the emmc through a USB adapter.
All produce the same failure to boot. Seems to also happen with uboot and towboot.
Here’s where things get interesting. Using towboot, I can boot to the emmc from the USB adapter. So the emmc is fine, but something about it being installed on the board is not.
Still trying to figure this out. Been very happy with armbian on the sd, and simply want it on the damn emmc
