Install Samsung Galaxy S3 I9300 Official Android 4.3 I9300XXUGMJ9, branded/unbranded firmware

For those who might not already known that the Samsung Galaxy S3 international variants (GT-I9300) has already received its official Android 4.3 Jelly Bean upgrade. The upgrade firmware came around as build number I9300XXUGMJ9, and this brought me up some doubt why the heck in the world happened that it is the same build number that has been previously leaked and then turned out to be official later.

This update has ben rolled out for unbranded Galaxy S3 in UK and for carriers like Vodafone, Swisscom, A1,  and among all other carriers in Europe regions. This update has now seen on Kies firmware server and should also be available via over the air update.  So better check it out now. The stock MJ9 firmware can be downloaded below, and can be flashed using Odin.

Odin Flashable Stock Firmware Android 4.3 I9300XXUGMJ9:

Unbranded:
Great Britain  - BTU_I9300XXUGMJ9 Link 1, Link 2
Carrier branded:
Czech Republic (Vodafone) – VDC_I9300XXUGMJ9 Link
Greece (Vodafone) – VGR_I9300XXUGMJ9
Ireland (Vodafone) – VDI_I9300XXUGMJ9
Romania (Vodafone) – CNX_I9300XXUGMJ9
Slovenia (SI.Mobil) - SIM_I9300XXUGMJ9
Austria (A1) – MOB_I9300XXUGMJ9
Switzerland (Swisscom) – SWC_I9300XXUGMJ9
Croatia (Vipnet) – VIP_I9300XXUGMJ9
[Download Link]

Tools:
Odin3_v3.07 Download
GT-I9300 USB Driver Download

1) Extract or unzip the downloaded firmware or stock ROM so that you’ll get the Odin flashable tar file which is looks likely the same as the image below.

2) Run Odin Downloader v3.07 flasher program.
3) Load the binary file. Click on the PDA button then browse to the folder where you extracted the stock ROM. like for example I used UK firmware so it goes like this

4. Do Not check the Re-Partition checkbox. Mark check these checkboxes Auto Reboot and F-Reset Time.
5. Reboot the phone in download mode: To reboot the Galaxy S3 into download mode , you need to turn the power off. After it completely shut down, just press and hold theVolume Down key, Home button and the Power ON/OFF button simultaneously.

Samsung Galaxy S3 Download Mode buttons – (Volume Down+HOME+ON/OFF)

You should then prompted into a warning screen and asking you to press volume up if you want to continue or volume down to cancel, just simply press volume up to get into download mode. The download mode then displays an Android robot and say’s “Downloading.. Do not turn off target!!”
6. Connect the phone to PC when it’s in the Download Mode screen.
7. Hit the “START’ button.
10. Wait until a word “PASS’ appears.
11. Remove the phone from PC once completely reboots.

Optional: perform factory reset to gain a fresher firmware installation, this is very useful to get rid of booting and  lag issues.

You may then confirm the newly installed Jelly Bean from your device:
Settings–>About Phone–>Software info or type *#1234# and see if it’s already I9300XXEMG4 4.1.2 Jelly Bean build.

If you can still hold your breath, just wait for the official Android 4.3 for our unbranded Galaxy S3 to arrived soon. And remember, If it takes too long enough, then there are still might be some issues that the developers are still cooking around.