Format SSD MMC

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Help tips for formatting:

  • SSD (internal or external)
  • MMC (μSD card - normal or recovery)
  • USB drive

Can be done either from the camera or PC, the required programs are:

  • fdisk - format into partitions
  • mkfs.ext4 - create filesystem
  • mkfs.vfat - create filesystem
  • dd - clean filesystem from the partition for fast recording



  • (not needed for USB) Check if SSD is connected to the camera:
    • The default connection is camera <=> internal SSD
    • For external drive set: camera <=> external SSD and power on the drive.
    • More info
  • Find out the device name:
$ dmesg
  • Check if it is already partitioned:
$ cat /proc/partitions
  • manage partitions:
$ fdisk /dev/sda
  • format a partition for file storage:
$ mkfs.ext4 /dev/sda1
  • for fast recording
    • Do not make a file system on the partition


The same as above except:

  • For internal SSD the connection should be set to pc <=> internal SSD



Make sure the camera is not boot from the MMC - in MMC boot by default the camera gets the boot files from /dev/mmcblk0p1 (FAT32) and mounts /dev/mmcblk0p2 (EXT4) as /.

  • check boot mode:
$ mount | grep " / "
  • check existing paritions:
$ cat /proc/partitions
  • manage partitions:
$ fdisk /dev/mmcblk0
  • format a partition for file storage:

mkfs.ext4 /dev/mmcblk0pX


  • Same as above except the MMC might be detected as /dev/sdX
  • If MMC is for boot the partition table type must be msdos, not gpt

'Erase' a file system from a partition

Sometimes there is a need to this:

  • if the drive was partitioned several times and the old file system journal starts from a location of a new partition - the file system will surely show up.
  • by accident


  • Use dd:
    • 'Erase' a filesystem from /dev/sda1
$ dd if=/dev/zero of=/dev/sda bs=1MB count=1 seek=1
  • 'Erase' a filesystem on /dev/sda2, if /dev/sda1 size is SIZE MB:
$ dd if=/dev/zero of=/dev/sda bs=1MB count=1 seek=SIZE
  • To erase the drive's partition table (better use fdisk):
$ dd if=/dev/zero of=/dev/sda bs=512 count=2

Useful links

  • git:elphel-tools-update -
    • the script is used to create a bootable MMC from a PC (the camera doesn't have parted and kpartx installed)
    • it has examples of using dd, parted, mkfs, kpartx
  • MMC boot
    • prepare a bootable μSD card and boot