I have an unusual .img file that I wish to mount on my Debian 7 system. I tried mount but that does not work:

sudo mount -t udf overlay1.img /mnt/vehicle/ -o loop
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

Next I tried to determine the partition system in this .img file:

sudo fdisk -l overlay1.img

Disk overlay1.img: 4 MiB, 4194304 bytes, 8192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xcd42b400

Device        Boot      Start        End   Sectors   Size Id Type
overlay1.img1 ?    3892371390 4109164418 216793029 103.4G 72 unknown
overlay1.img2 ?    3287936629 3304577640  16641012     8G  6 FAT16

Partition table entries are not in disk order.

Any suggestions on how to mount this file system are welcome. I have only worked with simple .iso mounts before and would like to learn how to mount these as well.

  • 1
    the output from fdisk seems totally bogus. Try file overlay1.img to see what type of file it is. – meuh Jul 31 '16 at 18:47
  • file overlay1.img overlay1.img: DOS/MBR boot sector – learnerX Jul 31 '16 at 18:58

If this is a normal "single partition" image then just try to mount it normally and let the OS auto-guess the type:

mount -o loop -r overlay1.img /mnt/vehicle

If this is a raw disk image, including all the partition data then you can use losetup to add the device

losetup loop0 overlay1.img

That will setup /dev/loop0. You can verify it's been setup with

losetup -l

Now you need to setup the partitions:

kpartx -av /dev/loop0

This will create the entries such as /dev/mapper/loop0p1 and /dev/mapper/loop0p2.

Now you can mount them

mount -r /dev/mapper/loop0p1 /mnt/vehicle

When you have finished:

umount /mnt/vehicle
kpartx -dv /dev/loop0
losetup -d loop0
| improve this answer | |
  • I am getting the following error: sudo kpartx -av /dev/loop0 device-mapper: resume ioctl on loop0p1 failed: Invalid argument create/reload failed on loop0p1 device-mapper: resume ioctl on loop0p2 failed: Invalid argument create/reload failed on loop0p2 – learnerX Jul 31 '16 at 18:56
  • That confirms the initial fdisk output - it looks corrupt; it's a 4Mb file but with a 100Gb partition inside? Looks wrong... You might want to examine it further with a hexdump (eg xxd) and look at the contents. – Stephen Harris Jul 31 '16 at 19:01

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