In order to hard reset a Sonim XP1, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Sonim XP1 device will be brought back to the default configuration of a brand new device.
2. Open Menu and go to Settings and Restore factory settings.
3. Type in the phone's password, 0000 by default.
4. Select OK and then Yes.
5. Wait for the phone to reset'n'restart. Done.