Preparing a USB device on Linux using .iso file

Last Updated : Aug 07, 2026 |
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Before you begin
Ensure the USB device has minimum storage capacity of 4 GB.
Download the .iso file as described in Software to download.
Caution:
This procedure is destructive. Any data on the USB flash drive will be destroyed with no warning. Make sure that you specify the correct drive, and make sure that this drive does not contain any data you want to preserve.
  1. Copy the Avaya SBC USB image file to the Linux system.
  2. Connect a USB flash drive to the system and execute the dmesg command.
    ADDITIONAL INFORMATION:
    The system displays a log detailing all recent events. At the bottom of the log, you can see a set of messages as a result of USB flash drive connection.
    [170.171135] sd 5:0:0:0: [sdb] Attached SCSI removable disk
  3. Log in as root: $ su -
  4. Specify your root password when prompted.
  5. Make sure that the device is not mounted. First, use the findmnt device command and the device name you found in the earlier steps. For example, if the device name is sdb, use the following command:
    ADDITIONAL INFORMATION: # findmnt /dev/sdb
    If the command displays no output, you can proceed with the next step. However, if the command does provide output, it means the device was automatically mounted and you must unmount it before proceeding further. A sample output will appear as specified below:
    # findmnt /dev/sdb
    TARGET   SOURCE   FSTYPE  OPTIONS
    /mnt/iso /dev/sdb iso9660 ro,relatime
    ADDITIONAL INFORMATION:
    Note the TARGET column. Next, use the umount target command to unmount the device: umount /mnt/iso
  6. Use the dd command to write the installation .iso image directly to the USB device:
    ADDITIONAL INFORMATION: # dd if=/image_directory/image.iso of=/dev/device bs=blocksize
    ADDITIONAL INFORMATION:
    Replace /image_directory/image.iso with the full path to the .iso image file, device with the device name as reported by the dmesg command earlier, and blocksize with a reasonable block size to speed up the writing process. The bs parameter is optional, but it can speed up the process considerably.
    ADDITIONAL INFORMATION:
    Note:
    Make sure you specify the output as the device name (for example, /dev/sda), not as a name of a partition on the device (for example, /dev/sda1).
    ADDITIONAL INFORMATION:
    For example, if the .iso image is located in /home/testuser/Downloads/rhel-server-7-x86_64-boot.iso and the detected device name is sdb, the command will be:
    # dd if=/home/testuser/Downloads/rhel-server-7-x86_64-boot.iso of=/dev/sdb bs=512k
  7. Wait for dd to finish writing the image to the device.
    ADDITIONAL INFORMATION:
    Note:
    Note that the system do not display progress bar. The data transfer process is complete when the # prompt appears on the screen. After the system displays the prompt, log out from the root account and unplug the USB drive.
    You can now use the USB drive as a boot device.