In order to hard reset a Bird S789, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Bird S789 device will be brought back to the default configuration of a brand new device.
I. Start by turning the phone on...
II. ... continue by using the phone's keyboard to type in one of these codes: *#77218114# or *#881188# or *#94267357# or *#9426*357# *#19912006# *#118811# *#3646633# ...
III. ... and complete by allowing the phone to restart. Done.