You can use an external CD drive that connects through USB, to reimage an appliance to the latest version.
Make sure that the CD drive is made bootable.
Use an image writing software to write the ISO image (bootable image) to the external CD drive.
Connect the CD drive with the bootable image to one of the USB ports on the appliance.
Log on to the appliance as administrator.
From the appliance console menu, select Reboot to restart the system.
Press F6 to enter the boot menu.
From the boot menu options, select the CD drive from which the appliance must upgrade.
The installation image starts loading. Wait until the install image gets unpacked and displays the Installation menu.
From the appliance console menu, select Reboot to restart the system.
Select the full installation mode, which is the default and the recommended option.
Follow the on-screen instructions to reimage the appliance.
When the reimaging is complete, remove the CD drive.
Caution
If you don't remove the CD drive, the appliance is reimaged from the CD drive after the next reboot, removing your current installation and returning the appliance to factory default settings.