We realize that all these different firmware options for various different Galaxy S3 smartphones might be a little confusing, so we thought we'd spell out just what you have to do if you want to manually install the latest official Samsung firmware version of Android 4.4 KitKat on your Galaxy S3 rather than wait around for the carrier rollout to happen.
Because it only takes one over the air update for a very nice person to make it available for everyone, as soon as the firmware is available for your model you can put it on your phone yourself rather than waiting for the carrier batching process which may have you waiting for weeks or even months to see the latest Android version. There's nothing dodgy about doing it this way either: Samsung even provides you with the tools to do it.
The updating process can be handled using two different tools. Samsung Kies is a manual updater that simply lets you push the latest firmware to your device rather than wait for the OTA. Because there's no guesswork involved it's super easy and straightforward. Simply plug your Galaxy S3 into your computer with a USB cable and let Kies do the rest. It will identify what firmware version you currently have and what the latest available version is. If there's new firmware available via Kies you can flash it and that's all there is to it. Odin is another manual updating tool that we'll use for this tutorial.
Updating with Odin
First up, you need to know your S3's model number: this is super easy to find (see above), just go to Settings and About Phone and you'll see your model number listed. This is really important as each individual model has different firmware. Trying to flash the wrong firmware could brick your device, especially if you have a carrier locked S3. In the US it's easy, because each carrier branded version has an easily recognizable model number. International S3's have the same model number but many different carriers. The difference is that technically you can flash any international firmware on any international S3. Note: the images below are for illustration purposes only, the information in the screen grabs may not be relevant to you and your device!
Once you know your model number you can visit Sam Mobile's firmware page and enter your model number to find the latest official firmware for your device. Look for your carrier in brackets after your country. It's safest to flash your specific carrier's firmware (make sure you have the right model number!) but not totally essential. The main difference is carrier bloatware but you could also encounter some issues with frequencies for the radio etc. It's better to be safe than sorry though. Some countries do not have any carrier-specific firmware, just a generic one. Once you've found your firmware just download it to your computer. If you're wondering what all the numbers and letters in the firmware mean, here's how to make sense of your Samsung firmware number.
Next, you need a tool called Odin. Odin simply lets you push firmware to your device, including custom ROMs. It can also be used to downgrade to previous firmware, but this process has been made much harder since Android 4.3 and the introduction of Samsung Knox. The process is simple: connect your Galaxy S3 in Download Mode to your computer and wait until Odin recognizes the connection, enter some information about the firmware and hit Start. Before we go into the step by step instructions, it's important that you back up any important data before proceeding, as you will lose your data in this process. If you're at all paranoid about your SD card or SIM card, just remove them before proceeding.
What you need to do
1. Make sure you have the correct firmware for your model number and carrier.
2. Download Odin, unzip it and open the program.
3. Make sure your Galaxy S3 has USB Debugging enabled in Developer Options. If you do not have access to this settings area already, go to Settings > About Phone and tap the build number repeatedly until the option is enabled. Make sure your device has at least 75% battery remaining.
4. Restart your Galaxy S3 in Download Mode: turn it off, then press and hold Volume Down, Home and Power until you see the Warning screen with the yellow triangle. From here press volume up to access Download Mode (aka Odin Mode).
5. Connect your S3 to your computer with a USB cable and wait for Odin to recognize it. If nothing happens, you may need to manually install Samsung drivers and then try again.
6. Click the PDA button (in Odin v3.07) or AP (in Odin v3.09) and navigate to the tar.md5 file in the firmware you downloaded.
7. Make sure repartition is not checked in Odin (Auto Reboot and F.Reset Time are ok).
8. Click start and wait until the process completes. Do not disconnect your device from your computer. You will see a Pass message and your S3 will reboot. Don't panic if it takes a little while. If you wait a long time you may be stuck in a boot loop. To get out of this you can re-flash the firmware again or do a factory reset using the hardware buttons. If you have issues, head to our forum for assistance.