Procedure to Update Galaxy S3 GT I9300 with Jellybean 4.1.2 Firmware:
- Download the Root Box Jellybean 4.1.2 Custom ROM Firmware and Google APPS Package from here to your computer. Once downloaded, connect your device to the computer with the help of original USB cable and place the 2 downloaded zip files in your device.
- Disconnect the device from computer and turn off your Galaxy S3 so that it can be entered in the recovery mode. Recovery mode in Galaxy S3 GT I9300 can be entered by holding the Volume Up button + the Home key button (the middle button). While holding these both buttons, turn ON your device.
- In recovery mode, select “Wipe data/factory reset” & “Wipe Cache partition”. If the device starts normally, then you will need to re try the process of entering the device in the recovery mode. You can also enter the device in recovery mode via the ROM Manager app.
- Select “install zip from sd card” > “choose zip from internal sd card” and then choose the Root Box Jellybean 4.1.2 Custom ROM Firmware and Google APPS Package which you have placed in your phone. It will take around 4 -5 minutes for applying the update.
- Once the update is applied, select the option of “Go Back” and “Reboot System now” for rebooting the device in the normal mode. Since it’s a first reboot, it will take more time than the normal mode as it has to finalize all the apps etc.
Note: If the device gets into the boot loop sequence or say gets stuck in the welcome screen, just re insert the battery and re follow the above instructions so as to again follow the above mentioned instructions.
Do share with us in the comments section just in case if you face any issues as we will try our level best to sort out the same. So there you go you have now successfully learnt on how you can upgrade your Galaxy S3 GT I9300 with the latest Root Box Jellybean 4.1.2 Firmware.