In order to hard reset a O2 XDA Terra, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
O2 XDA Terra device will be brought back to the default configuration of a brand new device.
1. Press and hold both Softkeys.
2. Take Stylus and press it into the hole on the upper left side of the phone.
3. Phone will reset and restart. Well done.