Firmware update version 3.4.3 to version 3.4.5 : 
1) Require flash burning procces - All settings will revert to factory default.

2) This specific FW version update require HDD formatting In the end of 
   the process to insure optimal performance of the device.

If the update is from version 3.4.5 to 3.4.5 with latest built date, can use normal update with de "TAR" file.
 no need for HDD format, in this case, and all settings will be kept.

Provision-ISR technical team.