A small tip while I’m playing with my Raspberry Pi, Docker and the love child of both, Hypriot:

If you want to mount an image of a block device you created with dd, you might encounter the problem that you don’t know where the partitions start. In past times I used either offsets or kpartx for that. Today I found an easier way on superuser, the losetup tool. With losetup the process is really easy. Just associate your image file with a new loop device mount the corresponding partition:

  losetup --partscan --find --show disk.img
  mount /dev/loop0p1 /mnt

If you’re done, umount and detach the file from the loop device:

  losetup -d /dev/loop0

It seems the –partscan function is fairly new and not every Linux distro has such a new losetup version. Then you can either upgrade the version or do it as our ancestors did, utilizing offset or using kpartx.