Samsung recently released a critical bug-fix update for Galaxy S3 I9305 LTE users via official Android 4.1.2 XXBLL5 Jelly Bean firmware (check out our step-by-step guide for installing firmware here). The firmware is supported for the UK and a few other European countries including Austria, Belgium, Germany, France, Hungary, Spain and Italy.
If you have already updated your phone to either Android 4.1.1 or the latest Android 4.1.2 official Jelly Bean firmware, then you can root your device using CF-Auto-Root and instructions provided in this guide. Rooting your device is essential to regain full system access, and be able to install third-party root-based apps or custom ROMs after installing the official Jelly Bean firmware. The CF-Auto-Root method described in this guide requires the use of flash tool like ODIN.
NOTE: Rooting your device will void its hardware warranty. However, you can reclaim the warranty by just reinstalling the official Jelly Bean firmware. Alternatively, you can run Triangle Away App after rooting to reset the flash counter and restore warranty status of your device.
- Verify that the correct USB drivers are installed for your Galaxy S3 I9305 LTE. Download Samsung Galaxy S3 I9305 LTE USB drivers.
- Users are advised to back up important data and settings to avoid data loss while rooting the device.
- Enable USB Debugging mode on your phone by navigating to Settings > Developer Options (if device is running Android 4.0 or later), else go to Settings > Applications > Development (if phone is running Android 2.3 or earlier).
- Make sure that your phone battery has at least 85 percent charge to prevent unexpected device shutdown (due to battery drain) while flashing the CF-Auto-Root tool using ODIN.
- Ensure that your device is unlocked and not locked to a specific carrier before you begin rooting.
NOTE: This CF-Auto-Root method works for both Android 4.0.4 ICS and Android 4.1.1/4.1.2 Jelly Bean firmware
How to Root Galaxy S3 I9305 LTE on Official Android 4.1.1 or 4.1.2 Jelly Bean Firmware
Step 1 - Download Root Android 4.1.1 / 4.1.2 for Samsung Galaxy S3 to your computer and extract the zip file.
Step 2 - Download ODIN v1.85 which is needed to root Android 4.1.1 or 4.1.2 on Samsung Galaxy S3 I9305 LTE.
Step 3 - Power off your phone and boot into Download Mode. To do so, press and hold Volume Down and Home buttons together, and then tap the Power button until the construction Android robot icon with a triangle appears on screen. Hit Power button again to confirm entry into Download Mode.
Step 4 - Launch ODIN on your computer and connect your phone to it, while your phone is still in Download Mode.
Step 5 - If your phone connects successfully, one of the ID: COM boxes will indicate yellow with the corresponding COM port number. This process may be time-consuming. So, do not interrupt the process.
Step 6 - Choose the files needed to be flashed or installed on your phone, which can be found among the extracted files in Step 1.
- Tap 'PDA' button and choose the file 'CF-Auto-Root-m3-m3zh-gti9305.zip'.
Step 7 - In ODIN, enable Auto Reboot and F. Reset Time options (by selecting checkboxes)
Step 8 - Hit Start button in ODIN and the CF-Auto-Root flashing process will begin. It will take a few minutes to complete.
Step 9 - Once the flashing is complete, your phone will reboot into Recovery Mode and install the root package. Now, your device's ID:COM box will also turn green.
Step 10 - When you see the home screen, disconnect your phone from the computer.
NOTE: if the device fails to boot into Recovery Mode automatically (as given in Step 9) just repeat the flashing process from step 6 again.
OPTIONAL: If all else fails just repeat the entire tutorial, but make sure that Auto Reboot option is NOT checked. Then after installation (Step 9), do the following:
Step 11 - Remove the battery and switch off the phone.
Step 12 - Reboot your phone by pressing and holding Volume Up, Home and Power buttons together to boot directly into Recovery Mode manually. This will start the manual rooting process on your phone.
Your Samsung Galaxy S3 I9305 is now successfully rooted on Android 4.1.1 / 4.1.2 official firmware update. Check for the SuperSU app in your apps list to verify.
[Source: Team Android]