In order to hard reset a BenQ-Siemens EF91, 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 EF91 device will be brought back to the default configuration of a brand new device.
1. Turn the phone on.
2. Now open the dialer and type in this code *#9999#
3. Done, the hard reset is complete. Not too hard if you ask me.