Still remember that “Swiss Army” toolkit for Samsung Galaxy S3 GT-i9300 (International Model) which can do many magic things including to root, flash custom recoveries (CWM v4 / Stock), backup / restore, full Nandroid via adb and so on? Well luckily this tool is now made available for three out of four released US variants of Galaxy S3. Sprint, AT&T and T-Mobile SGS3 users should now be happy.
The toolkit is designed very specifically so any non-Snapdragon Galaxy S3 should not use this tool, including its International Edition the GT-I9300.
Also, before installing this tool, make sure you disable your Antivirus / Internet Security app. You have to believe that this tool is clean and contains no virus at all.