First method:
- In order to switch off your device press the Power key for a
- short while.
- Then press and hold the Volume Down + Power button at the sime time for a couple of seconds.
- Finally, hold down the Volume Down to select option "Factory reset", and press the Power button to confirm.
- Well done! The hard reset is done!
Second method:
- The cell phone must be turned off, so hold down the Power key for a short while.
- Next, from Main Menu go to Settings and tap Backup & Reset.
- Afterwards choose Reset phone and select Erase all data.
- In this step tap OK to confirm your choice.
- Success! Your device is ready to use.
Third method:
- At the very beginning hold down the Power rocker for a few seconds until the phone is turned off.
- Then press and hold the Volume Down + Power button at the same time for a couple of seconds.
- Afterwards use the Volume keys to select option "Recovery", and press Power button to confirm.
- As soon as the phone's image appears on the screen hold down the Volume Up + Power key for a short while.
- Next select from Recovery Mode menu "wipe data / factory reset" using Volume buttons to navigate and Power button to confirm.
- In the next step choose "Yes -- delete all user data" to confirm the whole operation.
- After that select option "reboot system now".
- Well done! The hard reset has just been performed.
Hard Reset HTC Desire 820 - how to wipe your phone