I am sure it is doable. In that case there is gain in valuable lessons, besides saving money for an HDD. The cost is your time (unknown amount) and possible data loss (if the data is not important, you can wipe the disk immediately and save a lot of time )
If the data is of any value to you, now is the best time to get an extra HDD and start making back ups. Your future self will be grateful to you.
When moving from one ‘regular’ PC-style computer to another, switching HD’s is quite doable because the BIOS/UEFI abstracts enough of the hardware for Linux to keep running when the old disk is in a new computer. ARM devices are not so interchangable; from one Armbian to another Armbian I’d hesitate, but expect success. When moving from Raspbian to Armbian I have little idea what to expect, but it will involve handwork:
- Start flashing the Armbian image to SD card; for now be sure to get the Debian 10 based image (I expect you are not on the beta Yunohost 11)
- Install Armbian on your rock64
- Install Yunohost
- Copy (scp/other way) your Yunohost system backup to /home/yunohost.backup/archives
- Run ‘yunohost backup list’ to get the name of the backup
- Run ‘yunohost backup restore name_of_sys_backup’
Now the basics are in place, but on the SD-card.
If both ARM platforms are binary compatible, chances are you can edit your /ect/fstab to point to your USB HDD instead of your SD card. I expect it is all in a single partition, and that you will have to use bind mounts for the seperate directories in the root directory, except for /boot.
The bind mounts should mask the existence of the directory structure on the SD card, and let the booting Linux kernel use the directory structure on the USB HDD instead.
Unfortunately, when facing strange things later on (or earlier), you always first have to check whether it is because of a mismatch between the Raspbian roots of the USB disk and the Armbian running kernel, and wonder if it is a bug in the system or a bug in your migration.
That way it sounds like defeat If you can afford a second disk, this is really the reason not to postpone start making backups. The new disk should be large enough to serve as backup target and have enough space to restore the backup:
- install rock64-yuno on the new disk
- move yuno system backup to it, run restore instead of postinstall
- now connect the new disk to the old yunohost, and mount the new home/yunohost.backup/ directory over the old one, so that there will be enough space for the backup and that it will be in the right location
- with some Towers-of-Hanoi-scheme you can start with a backup of the largest app, reconnect the new disk to the new Yuno, restore the app from backup and upon success, delete the backup; now you have space again for the next app.
Roughly how much data will you be moving?