In a GNU/Linux system, the dd command must be used. This is a UNIX command that makes it possible to copy raw data, particularly adapted for copying on peripheral devices (in command line).

$ dd if=my_file of=my_USB_key bs=1M

The main options are as follows:

  • if=input file: reads this input file. This may be a file or a peripheral device. In this case, it is the restoration disk image.
  • of=output file: writes this output file. Likewise, this may be a file or a peripheral device. In this case, it is the USB drive.

For any further information:

$ dd –help
$ man dd

First, identify the destination USB drive for the copy. USB drives are generally mounted in Linux using the name "sdX" where X corresponds to a letter. The first USB drive connected and detected is named "/dev/sda". The second drive is named "/dev/sdb", and so on.

Other peripherals may also be mounted under this name – SCSI or SATA disks, for example. As the “dd” command makes raw copies, use it with caution.

Select the destination peripheral carefully - it must match the target USB drive. In our example, the USB drive ID is "/dev/sda". Replace this ID with your own.

Step 1: clear data on the USB drive

Erase all data from the USB drive.

$ dd if=/dev/zero of=/dev/sda bs=1M

This command will fill the USB drive with zeros.

Step 2: start copying

Start copying the downloaded disk image to the USB drive. Locate the path of the disk image. This is the input file to be written on the drive.

- or -

Next, copy the disk image.

$ dd if=/home/user/Desktop/USBKEY2.img of=/dev/sda bs=2M
- or-
$ dd if=/home/user/Desktop/usb-recovery-sn3kxa94f0035a8.img of=/dev/sda bs=2M

Once the copy is complete, the USB drive is ready to be used; unplug it.

Continue to the section Cabling SNS firewalls and booting on a USB drive.