Mostly note to my self for future reference.
What they don’t tell You in the tar backup tutorial is that it’s not enough to edit /etc/fstab (and their instructions for grub are for grub-legacy).
Because after restoring you probably have new partition UUIDs, you must:
- boot livecd
- mount your root fs
mount -B /dev /rootfs/dev, etc. (with proc and sys at least) to be able to chroot from livecd to your root fs
- edit /etc/fstab and change UUIDs there (new ones you can get using
sudo dpkg-reconfigure -plow grub-pcto automatically upgrade grub config files, just let it install to the drive(s) it was on
update-initramfs -uso UUID stored inside initramfs get updated, too
Then you should be able to boot it.