The Android 4.1 Jelly Bean ROM has been leaked and it is completely ready to be installed on your Samsung Galaxy S III. If you think you can accept the risk of device flashing, you may follow the below guide to Install Jelly Bean on your Galaxy S III GT-i9300 using this leaked ROM:
Remember: The warranty of your device will be expired if you root it. And you may also put your device at extreme danger of getting bricked or damaged. Hence, follow this guide at your own risk. We are not to blame if anything happens!
Note: You must have your Galaxy S III rooted and ClockworkMod Recovery should be flashed on it too. You also need to create a NANdroid backup as a precautionary step.
Guide to Install Jelly Bean 4.1.1 Leaked ROM on Galaxy S III GT-i9300
Step#1: First of all you need to download the Android OS V4.1.1 Jelly Bean Leaked Build: I9300XXDLG4 and ODIN v1.85 from this link.
Step#2: Now decompress both the zip files’ contents via 7-zip or any other appropriate utility.
Step#3: At this point, switch off your device and push and continue to hold the Home + Power + Volume Down buttons simultaneously to enter into the Download Mode.
Step#4: Now run ODIN on your computer that you had downloaded before.
Step#5: Now have your device connected with your PC via a USB cord. Upon connecting your device, a message will appear on ODIN to confirm that your device has been recognized.
Step#6: From the main menu of ODIN, click on “PDA” and select CODE_I9300XXDLG4_11164_REV00_eng_mid_noship.tar.md5 which should be found inside the Jelly Bean ROM file that you had decompressed in Step#2.
Note: You will need to uncheck “Re-Partition” and click “Start” to proceed.
Step#7: Now your device will enter into a boot loop. In that case, detach the battery and insert it again in your smartphone.
Step#8: At this point, boot your device into ClockworkMod Recovery by pressing down and holding the Home + Power + Volume Up together. Once your device gets booted into ClockworkMod Recovery, choose wipe data / factory reset.
Step#9: Now select “reboot system now”.
Now you have finally flashed the leaked Android 4.1.1 Jelly Bean ROM on your Galaxy S III i9300. Happy flashing!