In order to hard reset a Ericsson R520m, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Ericsson R520m device will be brought back to the default configuration of a brand new device.
1. Hello. Start by turning on your phone.
2. Now open Settings and choose Master Reset (press Yes to select/confirm).
3. If asked to, enter the phone's lock code (0000 by default).
4. Lastly, confirm your choice. The phone should now reset and restart. Good job.