In order to hard reset a Fly DS210, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Fly DS210 device will be brought back to the default configuration of a brand new device.
1. Power up the device.
2. Now enter the code *#987*99# into the phone and press Send to confirm it.
3. Wait for the device to reboot. Done!