In order to hard reset a LG GD910, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
LG GD910 device will be brought back to the default configuration of a brand new device.
1. Power up the phone.
2. Open the phone's dialer with a press of a Call button.
3. Now type this code into the dialer: either 2945#*101# or 1809#*101#
4. Lastly, press the Call button again. Your phone will now reset and restart. Well done.