Last Updated on September 1, 2024 by Mathew Diekhake

T-Mobile may have been in the news recently for selling 500,00 iPhone’s, but that didn’t stop the company from rolling out the official Galaxy S3 SGH-T999 firmware update to Android 4.2.2 CM10.1 M3 jelly bean devices. If you own the T-Mobile version of the Galaxy S3 SGH-T999 and you want to update the firmware to Jelly Bean, then check the full guide after the jump that will show you how to get it done.

As always, you can check out other Android firmware updates in our Android firmware section. We will be covering lots of them.

The M3 here means that it is the third coming of the original go at this. It’s common to see four of them, but at the same time this is coming towards the end of what we would call nearly a final build, so it is fairly stable to say the least.

It is custom being from CyanogenMod so that means if you had any withstanding warranty left it would revoke once you follow this guide. Not everybody had this though, unless extra money charges apply on top of your original price. If there wasn’t anything, that means you have nothing to lose.

It is the kind of Rom that is very popular for humanities who don’t want to toss away a lot of bucks on a new handset. By using this. Instead, it brings many of the features on a pay free type of software that they otherwise wouldn’t have had a chance to use. Now, since I am re-doing this post coming up to 2014 almost, there’s no reason users can’t upgrade to 4.2.2 on stock. In fact, we are no much past that even and well on our way to KitKat, that is all the way up to Android 4.4. It’s not the only reason, however. Some people just enjoy the Modding side of things, so this is something you want to check out if possible.

If you already have root access then you should be able to back up by using Titanium or at least taking a Nandroid. Usually we would say backup to the SD card internal storage, but that isn’t necessarily this time around. There’s not a valid or erroneous way of doing this. Some choose one way while others choose the other. Whatever tickles your fancy is excellent.

This update is a custom ROM update and not an official update by the T-Mobile team. That signifies that you will want to use ClockworkMod, or a custom recovery similar to get it done. This director will lead you through how to install CM10.1 M3 running the Android 4.2.2 Jelly Bean ROM.

Before you start, make certain you have the precise USB drivers installed in the Windows PC. Now let’s get started on the guide.

How to Install CM10.1 M3 Android 4.2.2 Jelly Bean on the Samsung Galaxy S3 SGH-T999

1 – Download the CM10.1 M3 Android 4.2.2 ROM, as well as the Google Apps pack from the Google Play store.

2 – With the USB supplied, connect the Samsung Galaxy S3 SGH-T999 to the Windows PC.

3 – Use the copy and paste feature to move the Android 4.2.2 ROM, zip and the Google apps zip over to the phones SD card root file.

4 – Power down the phone.

5 – Put the device into the ClockworkMod recovery mode.

6 – The first thing you should always do is the standard data wipes. It includes the cache data wipe, as well as the full data wipe. We also recommended, but not necessary, to clean the Dalvik cache. It is crucial you do this wiping proposed. Please note: In doing so you will lose all of your phone data, so make sure you have backed up the device already!

7 – Navigate your way back out the main recovery screen and select the option to install zip from SD card.

8 – Repeat the process, however, this time choose the option, choose zip from SD card.

9 – Repeat the process once more for the Gapps zip file. (Google Apps).

10 – Wait for the flashing process to complete. Navigate back by using the +++++Go Back+++++ option. From here select to reboot the machine. Upon reboot, the device will have the Android 4.2.2 CM10.1 M3 jelly Bean custom ROM installed.

11 – Remember to always right-click the USB logo in the Windows taskbar and click on the green arrow that states ‘safely remove hardware’ when you hover the cursor over it. Promptly right-click > select the gray zone >USB Mass Storage Device > stop button > select the flash drive in the ‘stop a hardware device’ section and click OK. It will now say ‘safe to remove hardware’ in a bubble that’s popped up on the taskbar