Create a disk image from a Raspberry Pi SD card

After setting up a Raspberry Pi with the desired software and configurations, create a disk image to replicate it on other devices.

Prerequisites

• 

•   Raspberry Pi

  With Raspberry Pi OS installed (ex: Prepare a Raspberry Pi from scratch)

• 

• SD Card

  With the installed software and configuration that you wish to clone

• 

• SD card reader

  To mount the source card to the Pi via USB

• 

• USB Key

  With at least 2x capacity of the source SD card to store the disk image

Connect to the Raspberry Pi   Part 1

1. Boot up the Raspberry Pi with the SD card containing the base Raspberry Pi OS. (not the card you would like to clone)

2. Connect to the Raspberry Pi with SSH or a monitor and keyboard.

3. Open a terminal on the Raspberry Pi.

Insert and identify the source SD card   Part 2

Using an SD card reader, insert the source SD card into one of the available USB ports on the Raspberry Pi.

1. Insert the SD card into the SD card reader.
2. Insert the SD card reader into an available USB port on the Raspberry Pi.
3. Identify the location of the SD card with the command: sudo fdisk -l

The output will include a list of block devices, including the SD card. The SD card will be identified as a block device, such as /dev/sda, /dev/sdb, etc...

It will appear similar to the following:

  Disk /dev/sda: 7.36 GiB, 7901020160 bytes, 15431680 sectors
  Disk model: Storage Device

While there are two partions on the SD card, (eg: /dev/sda1 and /dev/sda2), the partition that will be cloned is the entire disk, not just one partition. As such, we are interested in the block device, not the partition.

The block device id will look similar to the following: /dev/sda, /dev/sdb, etc..., it does not have a number at the end.

Insert and mount the USB Drive   Part 3

Insert and mount a USB Drive to which the disk image will be written

1. Insert the USB drive into an available USB port on the Raspberry Pi.

2. Identify the USB drive with the command: sudo fdisk -l

   The USB drive will be identified as a Disk, such as /dev/sda, /dev/sdb, etc... with the Device partions listed below it, such as /dev/sdb1, /dev/sdb2, etc... It will appear similar to the following:

     Disk /dev/sdb: 7.36 GiB, 7901020160 bytes, 15431680 sectors
     Disk model: Storage Device
     ...
     Device     Boot Start      End  Sectors  Size Id Type
     /dev/sdb1        8064 15431679 15429632 14.4G  b HPFS/NTFS/exFAT

   It is the identifier /dev/sdb1 that will be used to mount the drive.

3. Once you've identified the drive (ie: sda, sdb, etc...) from the command prompt on the Pi, mount the drive to a directory on the Raspberry Pi with the command: sudo mount /dev/sdb1 /mnt

   The /mnt directory is a common location to mount external drives. If you have a different location you would like to use, you can change this to a different directory. The directory name will be referenced in a later step.

Clone the SD card

With the Raspberry Pi setup with the SD card connected and USB Drive mounted, it's now ready to clone the entire contents of the SD card to a single *.img file.

1. From the command prompt on the Pi, change to the directory where the image is located on the USB drive with the command: cd /mnt

   If you mounted the SD card to a different directory, change to that directory instead.

2. Use the dd application to start cloning the SD card with the command: sudo dd if=/dev/sda of=pi-clone.img bs=4M status=progress   15+ mins
3. Once the dd process has completed, you can remove the source SD card if desired, as it's no longer needed for this process.

  Notes:

• The if parameter, eg: /dev/sda, /dev/sdb, is the location of the SD card, identified in Step 1, Part 2.
• The of parameter, pi-clone.img is the name of the file where the contents of the SD card will be written.
• The output file will be the same size as the SD card, so make sure you have enough space on the USB drive to hold the entire image.

Install PiShrink Part 1

From the command prompt on the Pi, complete the following steps:

1. Download the pishrink script from github with the command: wget https://raw.githubusercontent.com/Drewsif/PiShrink/master/pishrink.sh

2. Add execute permissions to the pishrink script with the command: sudo chmod +x pishrink.sh

3. Move the script to a folder for executables found in the path with the command: sudo mv pishrink.sh /usr/local/bin

Shrink the pi image Part 2

This next step will overwrite the original image file with a new, smaller image file. If you'd like to keep the original pi-clone.img, make a copy of it before proceeding.

From the command prompt on the Pi, complete the following steps:

1. Change to the directory where the image is located on the USB drive with the command: cd /mnt

   If you saved the image to a different directory, change to that directory instead.

2. Shrink and gzip the image with the command: sudo pishrink.sh -vz pi-clone.img   30+ mins

Example output from  pishrink.sh

PiShrink v24.10.23 - https://github.com/Drewsif/PiShrink

pishrink.sh: Gathering data
pishrink.sh: Checking filesystem
rootfs: 122290/445312 files (0.1% non-contiguous), 1018640/1808384 blocks
resize2fs 1.47.0 (5-Feb-2023)
pishrink.sh: Shrinking filesystem
resize2fs 1.47.0 (5-Feb-2023)
Resizing the filesystem on /dev/loop0 to 1463731 (4k) blocks.
Begin pass 2 (max = 8046)
Relocating blocks             XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 56)
Scanning inode table          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/loop0 is now 1463731 (4k) blocks long.

pishrink.sh: Zeroing any free space left
PiShrink v24.10.23 - https://github.com/Drewsif/PiShrink

pishrink.sh: Gathering data
pishrink.sh: An existing /etc/rc.local was not found, autoexpand may fail...
grep: /tmp/tmp.uGvlhvd09L/etc/rc.local: No such file or directory
Creating new /etc/rc.local
pishrink.sh: Checking filesystem
rootfs: 122290/445312 files (0.1% non-contiguous), 1018640/1808384 blocks
resize2fs 1.47.0 (5-Feb-2023)
pishrink.sh: Shrinking filesystem
resize2fs 1.47.0 (5-Feb-2023)
Resizing the filesystem on /dev/loop0 to 1463731 (4k) blocks.
Begin pass 2 (max = 8046)
Relocating blocks             XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Begin pass 3 (max = 56)
Scanning inode table          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/loop0 is now 1463731 (4k) blocks long.

pishrink.sh: Zeroing any free space leftpishrink.sh: Zeroed 1.8G
pishrink.sh: Shrinking partition
pishrink.sh: Truncating image
pishrink.sh: Using gzip on the shrunk image
pi-clone.img:	 78.9% -- replaced with pi-clone.img.gz
pishrink.sh: Shrunk pi-clone.img.gz from 7.5G to 1.3G

3. Once PiShrink has completed, safely unmount the USB drive with the command: sudo umount /mnt

  Notes:

• The -v tells PiShrink to be verbose
• The -z tells PiShrink to gzip the image
• The first argument, pi-clone.img is the source image file
• The second argument, pi-clone.img.gz is the destination image file that is zipped

---

Conclusion

That's it! You can now copy the pi-clone.img.gz file to your hard drive, upload it to a cloud storage service, or share it with others. It can be used to create a new SD card with Raspberry Pi Imager.

---

Where to next?

Continue exploring our open architecture and all its applications.

• 

• Directory of Devices

  Browse all device configuration tutorials and development guides.

• 

• reelyActive Developers

  Browse all developer documentation and tutorials.

• 

• reelyActive

  Together, let's make sense of things.