-s mount /dev/nbd0p5 /mnt/1
-s rsync -avhSAXP --numeric-ids /mnt/1/ root@tp:/mnt/root/root_ubuntubionic
-
-# on remote host:
-# mount boot and root to /mnt/1
-sudo -i
-cd /mnt/1
+mount /dev/nbd0p1 /mnt/1 # bionic
+mount /dev/nbd0p5 /mnt/1 # focal
+mount -o bind /mnt/root/root_ubuntubionic /mnt/2
+mount -o bind /mnt/root/root_ubuntufocal /mnt/2
+mkdir -p /mnt/2/boot
+mount -o bind /mnt/boot/boot_ubuntubionic /mnt/2/boot
+mount -o bind /mnt/boot/boot_ubuntufocal /mnt/2/boot
+# S = sparse, A = acls, X = xattrs
+rsync -ahSAX --numeric-ids /mnt/1/ /mnt/2
+
+cd /mnt/2