Eliminates random reboots, battery drain bugs, and application crashes found in experimental custom ROMs.
Connect your Galaxy S3 to the PC using a USB cable. One of the ID:COM boxes in Odin will turn blue, indicating a secure connection. Click on the (or PDA in older Odin versions) button. Browse and select the extracted .tar.md5 firmware file. Eliminates random reboots
: The most well-known and comprehensive archive of Samsung firmware. It has a dedicated section for the GT-I9300. While free downloads are available, they are often slow. A premium account is required for high-speed downloads. Here is a direct link to the firmware page for GT-I9300: battery drain bugs