[en] Fixing Ubuntu boot process after restoring tar backups to newly formatted disk (with UUID changed)

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
  • chroot /rootfs
  • edit /etc/fstab and change UUIDs there (new ones you can get using blkid
  • do sudo dpkg-reconfigure -plow grub-pc to automatically upgrade grub config files, just let it install to the drive(s) it was on
  • do update-initramfs -u so UUID stored inside initramfs get updated, too

Then you should be able to boot it.