In order to hard reset a Sonim XP3400 Armor, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Sonim XP3400 Armor device will be brought back to the default configuration of a brand new device.
1. Turn on the phone.
2. Select Menu, then Settings and Restore factory settings.
3. Now enter the phone's passcode - default passcode is 0000.
4. Your phone will now reset and restart, completing the hard reset.