*#*#7780#*#*
This code can be used for a factory data reset. It'll remove following things:
- Google account settings stored in your phone
- System and application data and settings
- Downloaded applications
It'll NOT remove:
- Current system software and bundled application
- SD card files e.g. photos, music files, etc.
Note: Once you give this code, you get a prompt screen asking you to click on "Reset phone" button. So you get a chance to cancel your operation.