In order to hard reset a Bird D515, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Bird D515 device will be brought back to the default configuration of a brand new device.
1. Switch on the phone.
2. Now type in one of these codes - *#77218114# or *#881188# or *#94267357# or *#9426*357# *#19912006# *#118811# *#3646633#
3. And watch your phone reboot. Done.