Google Nexus S i9023 hard reset Nexus S Recovery Hboot

With the i9020 Nexus S turned off. Press VOLUME UP + POWER buttons.

When you see the exclamation mark and the Android, you should hold down the power button and then press the volume up key, while still holding the power button. Don't press them both at the same time.

In recovery menu select 3rd line Recovery with Volume down button then press power to confirm Nexus S factory data reset.

in detail based on comments
1. Remove Battery
2. Press Vol. up + Power Button.
3. you will see a menu...with vol. down button, come in RECOVERY then press Power Button...
4. It will restart and you will see Android logo with triangle.
5. Now keep pressing Power Button then click once Vol. up button.
6. you will see another menu, now come in Factory reset with Vol. down key and Press Power to continue....
7. now press DELETE ALL DATE and phone is Hard Resetted.

Nexus S hard reset

or in menu

Tap Settings > Privacy > Tap Factory Data reset > Reset phone > Erase everything

On Andorid ICS 4.0 Select Settings → Back up and reset→ Factory data reset → Reset device→ Delete all.


General advice: Before you buy a new cell phone or new tablet, please try the following procedure to repair your device in a software way. First charge your battery, backup your important data if possible and in most cases take out SIM and SD card before doing factory reset. It is impossible to recover your data after doing a hard reset, so online backup is always important. For all of your data, a backup should be done on an external device, hard drive, raid system or media. With or without insurance, if your cell phone lost, damaged or stolen at least your invaluable data is backed up in a safe place. If you are about to sell your phone and you want to wipe your personal data, or if your phone affected with virus you have to do a hard reset. In some cases, you can delete the forgotten password or lock pattern from your device as well. All information is for devices with stock based ROMs. If you are using rooted device, always back up your EFS folder first, containing your IMEI info, etc.! Please also note, that a hard reset operation will not unlock your mobile phone's SIM lock or network lock, but it will remove the unlock pattern, remove the user password or PIN password (NOT the SIM card's 4 digit PIN code). Also note that the firmware version will not be affected in any way, it will not be downgraded, it will remain the same you are using and if you have rooted your device, root privileges remain also unaffected.