The Samsung Galaxy S3 is turning into a secondary smartphone for many since it’s aging rapidly. Today the Samsung Galaxy S5 is out and that makes the S3 far more expendable. As you probably know, applying root access is taking away the default factory restrictions in place by the manufacturer. That’s why when we following steps like this the warranty is immediately void. The only way to have the warranty working again is to unroot the same. That said, most of you won’t have any warranty remaining since the mobile is several years old now.

If you are on your S3 then you will open up the operating system to tons of new possibilities including custom ROMs, custom recoveries, custom firmware and extra applications from the Google Play store that you couldn’t use without the internals unlocked.

S3

The tool we are using today is the CASUAL rooting tool that works from the scripts as the CF-Auto-Root by our beloved Chainfire. We consistently use Chainfire’s work here on site because we love the close to stock Android experience and it’s easy. Correspondingly, this method is quick and easy too. The developer of casual is Adam Outler — the same man who unlocked the bootloader of the Note 2 for Verizon subscribers.

Casual works with Windows, Mac and Linux computers, notebooks or laptops that have the USB slot on the side. Adam says that the Mac version is still in ‘experiential’ stages so you may want to use one of the other options instead. We must have the slot because we are connecting our handsets to the computer. Files are often downloaded to the computer before being transferred over to the mobile device because it’s safer.

  • Use this tool only for the SGH-i747 model of the Samsung galaxy S3 smartphone. You can anytime check your phone’s version in the ‘About Device’ menu.
  • Do not try attempt to flash the file in this post on any other Android device. It doesn’t work and it can cause soft-bricking.
  • Download and install the latest Samsung USB Drivers on your computer. You can find them from third-party links, the official Sammy website or with Kies. Similarly, you may wish to install Samsung kies and install the drivers that way.
  • You must backup the device if you lose data. Backup the phone contacts, call logs, MMS texts, SMS messages, videos, pictures, music and all other data. Download Helium from the Play Store if you don’t know any apps for making copies of the data. Helium syncs the contacts, backs up the messages and market apps. Moreover, you should make a copy of the EFS folder for when it is corrupt.
  • Disable Kies before you start the guide below and after you get the drivers.
  • Temporarily disable all antivirus from the Android and the computer. It comes from apps on Mobile and you can visit the system tray to disable security from Windows.
  • Do not go past this point unless you are an advanced Android user.
  • Check the battery charge level from the status bar. It wants to have at least 60% battery power before starting. The guides short, but the device is old and that’s why we want to save up some extra power. Some of you will have USB charging working so the battery charges when it’s plugged into the computer.
  • This method is not tested on the Windows 8 OS or the Raspberry PI. You are safer using Windows 7, OS X mountain Lion, OS X Lion, Debian Linux 64 and 32 bit.
  • You must be running the latest version of “java” on the computer. Check the system tray for any java updates. If there aren’t any ready for installing you are likely running the latest version. If you don’t see java you must download the file from the official website.
  • After completing the guide the KNOX flags will be triggered and it loses the warranty. If you are satisfied with all that it’s time to start the steps.

How to root the AT&T Samsung Galaxy S3 SGH-i747 using the CASUAL package

  1. Turn the computer on and log in to the user account of your choice.
  2. Download the casual file from this page to the desktop of the computer.
  3. Double click the jar file on the desktop and launch the program.
  4. Find the USB cable for the mobile.
  5. Boot the S3 in Download mode
    – press Volume Down + Power + Home keys at the same time.
  6. Connect the S3 to the computer using the USB wire.
  7. Look at the bottom of the screen for a message saying “device connected.”
  8. Press the “do it!” button just above where it says device connected.
  9. Wait for the flashing to finish.
  10. Do not touch any buttons until it finishes.
  11. Disconnect the mobile from the computer safely by stopping the USB mass Storage device.

If you get stuck in a boot loop you must enter the recovery mode. From there select ‘wipe data/ factory reset.’ Download the Root Checker Pro application from Google Play to check it’s working.