EXFO FTB-1 - Manual (Page 218)

Troubleshooting
208 FTB-1
Restoring Your Unit to Normal Operation
To verify disk integrity:
1. Turn on the FTB-1.
2. While the system is displaying the boot menu (3 seconds), press
the down arrow from the unit’s keypad to select the Maintenance and
recovery mode.
OR
Press the ARROW DOWN key on the keyboard (if you have connected
one).
3. Press from the unit’s keypad or ENTER on your keyboard to
confirm your choice.
Note: The touchscreen becomes effective at this point.
4. From the main window, select Check disk integrity, then tap Next.