Here we will see how to install a modified recovery on Galaxy S3.
For the purpose we will use the ClockWorkMod Recovery 6, the latest available and one of the most advanced in existence (for further information see

WARNINGS

• Read the Guide and then follow it point by point as it is and without doing anything .
• These guidelines will void warranty officially.
• You can no longer perform updates via OTA or KIES.
• As with all operations of modding, the liability for damages is only of those who decide to change their phone.

PREREQUISITES

• To install the recovery changed use Odin (the version you choose is indifferent) DOWNLOAD
• Make sure they are installed in the Pc phone drivers (just the presence of Kies)
• Download the recovery package for Galaxy S3 from recovery-cwm-touch-6.0.2.7-i9300.tar
  
  

How to Install Clockworkmod recovery on Galaxy S3

1. Run Odin and PDA field choose the recovery package previously downloaded .tar.
   Make sure the Auto Reboot entries and f. Reset Time are active (the graphics might change depending on the version used odin).
   
   
2. Put Download Mode your phone.
   By phone off press the buttons VOLUME down + HOME + POWER until you see the following screen appears.
   
3. Confirm by pressing the VOLUME UP button.
   
4. Now you can connect your device to your pc via usb cable.
   Wait that odin recognize the phone.
   
5. Start the installation process by clicking on the Start button of Odin.
   The operation will last a few minutes and after the Galaxy will restart by itself.
   
6. Congratulations, you have installed the ClockWorkMod Recovery.
   To enter, phone off press the buttons VOLUME UP + HOME + POWER.
   There you will see a screen similar to the following:

The quickest method to uninstall the recovery is to flash with odin the firmware in use (data will not be erased).