Panasonic KX-UT670 Administrator's Manual page 225

Note
•
After the restoring is completed, the unit will restart automatically.
•
You cannot operate the unit during the restore.
•
If the unit's firmware version changes between backup and restore, the data cannot be restored.
•
If restoring fails, the unit enters recovery mode. After recovery, the unit will restart automatically.
Document Version 2012-07
Section 8 Backup and Restore
Administrator Guide 225