In order to hard reset a BenQ-Siemens SL80, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
BenQ-Siemens SL80 device will be brought back to the default configuration of a brand new device.
1. Switch on the phone.
2. Type in this code - *#9999#
3. Watch as your phone restarts, completing the hard reset.