[Guide] How to root the Samsung Galaxy S III (AT&T)

The Samsung Galaxy S III for AT&T in the U.S. features a 4.8 inch Super AMOLED HD display, 8 megapixel intelligent camera in the rear which is capable of 1080p HD video capture, a secondary front facing camera, up to 64GB of internal storage which can be expanded through microSD, LTE connectivity and is powered by a dual core processor and 2GB of RAM.

The following guide will show you how to root your Samsung Galaxy S III for AT&T




[NOTE] This root method is only valid for the U.S. variants of the Samsung Galaxy S III for AT&T. You can find the guide to root the International variant (GT-i9300) here.

[DISCLAIMER] This website will not be responsible for any loss of data or device malfunction which may occur through following this guide. Please do not proceed unless you are well aware of these risks. Remember that you are proceeding at your own risk.

1. Download and install the USB Drivers for the Samsung Galaxy S III.
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2. Enable USB Debugging under Settings > Developer Options on your device.
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3. Connect your device to your computer using the USB cable.
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4. Download CMW_SuperUser_v3.07.zip and transfer it to the root directory of the internal storage of your device.
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5. Disconnect your device from your computer and turn it off.
   
   
   Flashing ClockWorkMod
   
6. Download and extract ODIN 3.04
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7. Download fixboot.tar-
8. Turn your device on using Down + Home + Power buttons simultaneously
• Your device will boot into Download Mode.
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9. Run Odin3 v3.04.exe from the folder you downloaded in Step 6.
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10. Connect your device to your computer
• Wait for ODIN to detect your device.
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11. On ODIN, click PDA and select fixboot.tar from Step 7.
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12. Make sure Auto Reboot and F.Reset are selected and click Start to begin the process.
    
    
    Flashing SuperUser
    
13. Switch your device off
    • Hold Volume Up + Home + Power buttons simultaneously.
    • Your device will boot into ClockworkMod Recovery Mode.
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14. Navigate to install zip from sdcard > choose zip from sdcard > and select the CMW_SuperUser_v3.07.zip you downloaded in Step 4.
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15. From the Main Menu reboot your device.
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16. Install BusyBox from the Google Play Store
• Grant it SuperUser permissions and follow onscreen instructions.
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17. Launch the SuperUser app and update the binaries by selecting the Settings Icon > Su binary > Update

That’s it. Your Samsung Galaxy S III for T-Mobile has now been rooted.


source – XDA Developers