First of all, thanks for this post! It helped me.
Sorry to revive an old post but I followed the steps and read in the replies that a boot partition was not needed but I did not see a solution to NOT using the boot partition.
The armbian installer does not copy the boot partition from the SD card so I manually copied the folder data and it am now booting off my NVME.
instead of step 4:
sudo mount /dev/nvme0n1p1 /mnt
// Now copy the sd card boot contents to the nvme. (The boot partition on the SD needs to be mounted)
sudo cp -R /boot /mnt
Then continue to step 5
