In order to hard reset a Ericsson GH 337, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Ericsson GH 337 device will be brought back to the default configuration of a brand new device.
1. Turn on the phone.
2. Open Settings and Master Reset.
3. Type in the phone's lock code.
4. Confirm the operation. Done.