Tips & Tutorials

Update Galaxy S3 I9300 to Android 4.2.1 CM10.1 Jelly Bean Custom Firmware

You can now enjoy a bit of Android 4.2.1 Jelly Bean on Galaxy S3 I9300 with the latest CyanogenMod 10.1 experimental custom ROMs. CM10.1 custom firmwares are all based on the latest Android 4.2.1 from the AOSP and includes most of the CyanogenMod mods and patches that you are used to enjoy. You can update Galaxy S3 I9300 to Android 4.2.1 CM10.1 Jelly Bean custom firmware using the tutorial below and try out this CyanogenMod ROM. Don’t forget to try out the new Camera app and new Android keyboard in Android 4.2.1 Jelly Bean.

As you continue reading below, we will guide you through the entire process of how to install Android 4.2.1 CM10.1 Jelly Bean on Galaxy S3 I9300 with complete steps. Don’t forget to read all the tips below that you have to keep in mind before proceeding. Please make sure you backup all your data as given below because this tutorial will wipe your data. Remember, this is a custom ROM, not an official firmware update by Samsung. Let’s get to the tutorial now.

Disclaimer: All the custom ROMs and firmwares, official software updates, tools, mods or anything mentioned in the tutorial belong to their respective owners/developers. We ( or the developers are not to be held responsible if you damage or brick your device. We don’t have you on gun point to try out this tutorial 😉

Android 4.2.1 CM10.1 Jelly Bean Custom Firmware Details:

NOTE: Since this is a nightly build, make sure you know that after installing this firmware update, your Android device can get FC errors, boot loops, several other bugs, apps might not work or worse, your phone might not boot. To fix, you will have to reinstall stock firmware or any other stable custom ROM.

You might want to read this: How to Install ClockworkMod Touch Recovery on Galaxy S3 I9300.

Android 4.2.1 CyanogenMod 10.1 Known Bugs for Galaxy S3:

Here is a list of all the not-working features and known issues of this ROM at the moment.

  • UI: Apps like NHK are broken
  • Camera: Recording effects broken
  • Camera: Touch 2 focus issues with enabled flashlight
  • Bluetooth: doesn’t pair
  • Bluetooth: audio streaming sometimes becomes laggy or stops at a distance > 1m
  • FM Radio: unsupported
  • TV Out: unsupported, will never work (proprietary, undocumented)
  • Lots of missing and yet unimplemented features

Samsung Galaxy S3 USB Drivers

You will need to connect your Android phone with the computer. For that, please make sure you have installed the USB drivers for Samsung Galaxy S3 properly. If not, you can download the latest official drivers from our Android USB Drivers section here:

Download Samsung Galaxy S3 USB drivers!

Backup and Other Important Tips

Done with the USB drivers? Perfect. The tutorial is on the next page, but first, please take a look at the following tips and important points you need to take care of. These are important, as we don’t want anyone losing their personal data or apps:

Always backup your important data that you might need after you install a new custom ROM, an official software update or anything else. Make a backup for just in case, you never know when anything might go wrong. See below for some tips on how to backup data:

Samsung users can also back up data using Samsung KIES. If you backup data manually, you get more options what to choose from and it is very easy to move data across Android devices from different manufacturers, i.e moving Samsung Galaxy Note backup data to HTC One X.

If you already have a custom recovery (ClockworkMod, TWRP etc.) installed on your phone, we strongly recommend a backup using that as it creates a complete image of your existing phone set up.

A few more optional tips that you should remember:

1. Having problems connecting your Android phone to the computer? You need to enable USB debugging mode. See here: How to Enable USB Debugging — for Gingerbread, Ice Cream Sandwich and Jelly Bean.

2. Make sure your Android device is charged up to 80-85% battery level. This might help you: How to Check Battery Percentage. Why? Because, if your phone goes off suddenly while installing a custom ROM, flashing an official firmware update or installing mods etc. — your phone might get bricked or go dead permanently. No one wants that, right?

4. Most of the tutorials and how-to guides on Team Android are for factory unlocked Android phones and tablets. We recommend NOT to try our guides if your phone is locked to a carrier, unless we have specified the carrier name or device model.

If you find the above tips useful and they were helpful to you, please consider giving us a +1 or LIKE to thank us!

UPDATE: Official Android 4.2.1 CM10.1 Jelly Bean nightly builds are now out! Read the full tutorial here!

All set and ready? Good. Now, let’s proceed with the tutorial on the next page and update Galaxy S3 I9300 to Android 4.2.1 CM10.1 Jelly Bean custom firmware.

About the author

Haris Nadeem

He lives on everything Android; has countless devices, apps and games to play with everyday. Currently serving as the Chief Editor at Team Android.


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