The I939 is the China variant of the Samsung galaxy S3. If you are living in China you now get to have a taste of the 4.1.2 Jelly Bean, official firmware by getting your hands on this update. It will have rolled out over the air in some regions. You can also download the update via Samsung KIES.

Oh yeah, don’t you just love when you get to taste some new Jelly Bean? I sure do and I hope you do as much as me. So what does this one have in it. We spend a lot of time covering it so we are almost experts by now to comment on it. The only real challenging part is making sure we comment on the right build because we cover so many of them. This one is fairly easy to understand because it’s all about the smoothness and not features. It’s so smooth and runs so well that you will instantly notice the difference when compared to the older version you would have run. This alone is enough to keep you occupied and really happy with the new download you just installed. OK, so when we say smooth what exactly are we talking about. Pretty much as soon as you unlock it and browse around anything. It doesn’t matter if it’s applications or settings or whatever it might be, it will be like clockwork and really stable. There will be no hesitation and it will be really responsive in doing what you ask of it. Kind of like if you just installed lots of new memory in your computer and all of a sudden it just works again.

This is an official update from the real Samsung team. That means your warranty and all things of that nature will still be fine. That only applies if you have one in the first place because not everybody does. You generally need to pay extra money for this when you originally purchased it. This will be the case for most parts of the world that I’m aware of. If you live somewhere where that is not the case then please let us know in the comment as you can teach us something and we can mention this in our posts.

You need:

– Samsung Galaxy S3 I939 USB drivers.

– USB debugging mode enabled

Also note that going ahead with this ZTCMF2 update will cause you to lose any changes and/or customization you might have on the mobile. You can put all of this back most of the time once you have finished.

The Guide

Step 1. Download the 4.1.2 ZTCMF2 firmware, followed by the Odin 3.07. Extract both of the files to an easy place.

Step 2. Power down the Galaxy S3 I939 and boot it up into download mode.

Step 3. Open the ODIN up which we downloaded earlier.

Step 4. Connect the Zoom to the computer via the USB cord.

Step 5. Using the ZTCMF2 file we extracted, you need to fetch out the code file and upload it to the PDA button, on the right side of ODIN.

Step 6. Now click the start button inside ODIN. This will begin flashing the device.