Hard Reset Format Samsung i9100 Galaxy S2

There are three ways to hard reset this model.
Hard Reset Samsung Galaxy S2 with Dialer Code:

1. Turn on Samsung Galaxy S2
2. with dialpad number, press *2767*3855#
3. Then the Samsung Galaxy S2 will reset all you data and back to Factory Default

Hard Reset Samsung Galaxy S2 with Hardware Button:This is the way to Hard Reset Samsung Galaxy S2 back to factory default using  hardware button, this option can be done when we can not access the menu or the Samsung Galaxy S2 can not run properly. This is what we have to do :

1.  Remove the Battery for 10 seconds
2. Put The Battery at the position again
3. Press together and hold: VOLUME UP + HOME BUTTON (press continuously and go to step 4, but remember Do Not Release this step 3 button) 
4. Continue with pressing POWER BUTTON about 3 seconds dan release POWER BUTTON after that (when pressing POWER BUTTON, do not release VOLUME UP + HOME BUTTON at step 3)
5. You will see Recovery menu, Choose WIPE DATA/FACTORY RESET. At this point, to ENTER press POWER BUTTON, to NAVIGATE press VOLUME UP and VOLUME DOWN (depend on what we need). This is the end of step.
6. Note: For step 3, HOME BUTTON locate in bellow LCD in the middle button.

Hard Reset Samsung Galaxy S2 with Software:If we still can access the menu, the easy way to hard reset using Setting function by pressing :
Menu > Setting > Privacy > Factory Data Reset > Reset Phone 
This is the way to erase all data on Samsung Galaxy S2, such as Google Account, Contact, SMS, application and it settings. After doing the Reset Phone by Software then Samsung Galaxy S2 will run automatically and process to delete the data back to factory default.