Te lo pongo en inglés que se entiende de sobras. Si necesitas traducción de algo avisa!
Performing a factory reset using phone buttonsIf you can’t turn your phone on or access settings, you can still perform a factory reset by using the phone's buttons.It’ll permanently delete all your data and customized settings! Be sure to back up any data and files you want to keep...
1. Turn the power off.
2. Press and hold the VOLUME UP and VOLUME DOWN buttons, and then press and hold the POWER button. Release these buttons when your phone turns on and displays a text screen.
3. Keep pressing the VOLUME DOWN button until the Factory reset option is highlighted, and then press the POWER button.
4. Follow the instructions onscreen to proceed with the factory reset