In order to hard reset a Grundig I908, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Grundig I908 device will be brought back to the default configuration of a brand new device.
1. Make sure that the phone's display is turned on by pressing the Power button.
2. Starting from the Main Menu, select Settings > Backup & Reset.
3. Now select Factory data reset > Reset device > Erase everything.
4. The hard reset is now complete.