Explains on how to mount an image (dd copied) from a disk containing multiple partitions.
The command losetup sets up the device scanning for partitions.
The image and partitions are here mounted read-only as precaution only.
losetup --partscan --find --show --read-only <img-path>
On success, it reports the loop device /dev/loopX in the output.
When looking in to the devices the partitions are visible as /dev/loopXp1 and /dev/loopXp2 and so on.
To remove the device(s) use the detach option on the new created loop device.
losetup --detach <loopdev>
mount -o read-only /dev/loopXp1 /mnt/<mount-dir>
Use fdisk to find partitions sector offsets and the sector size.
fdisk -lus <img-path>
Needs calculation for the byte offset of the sector for the partition using a calculation.
mount -o loop,ro,offset=$(expr <offset> \* <sector-size>) <img-path> <mnt-dir>
Command(s) to save a disk image in a zipped form using a pipe to gzip.
dd if=/dev/sdX status=progress | gzip -c > gzip-file-out.img.gz
Command(s) to restore a disk image in a zipped form using a pipe to gzip.
gunzip -c gzip-file-in.img.gz | dd of=/dev/sdX status=progress
When a disk image is restored the partitions get the same UUID used by the original.
To have a different UUID a new one must be generated using uuidgen
uuidgen
tune2fs /dev/sdXN -U <the-new-uuid>
Or all at-once
tune2fs /dev/sdXN -U $(uuidgen)
The system might be complaining before executing a check must be performed on the partition.
e2fsck -f /dev/sdXN