EXFO FTB-2 - Manual (Page 292)

Troubleshooting
282 FTB-2 and FTB-2 Pro
Restoring Your Unit to Normal Operation
Restoring Your Unit to Normal Operation
If you ever encounter major problems with your unit (for example, the unit
does not behave the way it used to), you can revert it to a previous state.
You can revert your unit either to its initial state (as it was at time of
purchase), or to a specific state with a backup image (WIM file) created
previously.
Note: For current updates, use Update Manager.
You can create your own WIM files directly from your unit and store them
on a USB key for future use.
I
MPORTANT
The WIM files that you create are based on the serial number of
your unit. This means that the WIM files created on one unit are
only valid to restore this particular unit.