force reset Reset the device (press and hold POWER button for 8-10 seconds)
Unlock Galaxy S3 T999 i747 i535 using hard reset
sgs3 hard reset or reset Galaxy S3: PRESS AND HOLD VOLUME UP + Home Button + Power
Turn the phone off.
Press and hold VOLUME UP and Home(center) button
Press Power until the phone vibrate
Wait until you see the Android logo then release all the buttons.
Select Wipe data/Factory reset with VOLUME DOWN, press Power (right hand-side)
Select YES -- delete all user data with VOLUME DOWN and then press Power
After format, press Power again to reboot phone. (select reboot system now)
If your device is frozen and unresponsive, press and hold for 8-10 seconds. The device will reboot automatically.
If this does not solve the problem, perform a factory data reset. In Idle mode, open the application list and select
Settings → Back up and reset→ Factory data reset → Reset device→ Delete all.
or Factory format entering sgs3 format code
Use this method to hard reset your Samsung Galaxy S III: Enter *2767*3855#. Warning! All your data including contacts, messages etc. will be lost! Copy all your necessary data/Contacts/Messages etc. to SIM or make backup to your PC before full reset! Take out SIM card before full reset.
Note: If you reset your device to the factory defaults with SD card encryption setting enabled, the device will not be able to read your encrypted files. Disable this setting before resetting the device.
sgs3 firmware flash download mode: PRESS AND HOLD VOLUME down + Home Button + Power on
unlock gs3, how to reset i9300, sgs3 reset,