In order to hard reset a Ericsson GA 628, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Ericsson GA 628 device will be brought back to the default configuration of a brand new device.
1. Turn the phone on.
2. Now scroll down to Settings, press yes, select Master Reset and press YES again.
3. Type in the phone's lock code, 0000 by default.
4. Press Yes one last time to confirm the operation. Done.