In order to hard reset a BenQ-Siemens S88, 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 S88 device will be brought back to the default configuration of a brand new device.
1. Turn on your device.
2. Use its keyboard to type in this code - *#9999#
3. The device will now restart.