Press the Call/Green key (or the Power key ) to select it.
Ensure the battery has at least 30% charge to avoid shutting down during the process. How to Hard Reset NOKIA 5310 2020 Dual SIM
Use the Volume Down (-) key to scroll down until you find: "Clear eMMC" or "Factory Reset" Note: On some firmware versions, it is labeled "Clear Storage." Press the Call/Green key (or the Power key ) to select it