I've done a bkup_rpimage
onto a USB3 drive using:
https://github.com/lzkelley/bkup_rpimage
From: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=12079
But try as I may, I haven't found a tutorial or post showing how to restore. Must exist, though ?
Just looked through all the possible answers that Search threw up here. Nothing definitive that seems to anser the question. I've done a full /home backup to a USB3 external drive using Deja Dup and this programme does offer a Restore option.
Doesn't answer the /rootfs backup/recover question. I did the bkup_rpimage install/backup to the external drive ... no answer to "how to restore" that I've found. Confusing - a backup with no restore capability ?