Update Galaxy S2 I9100 to Android 4.2.1 Jelly Bean CM10.1 Nightly Custom Firmware
CyanogenMod 10.1 nightly releases are now available for Galaxy S2 I9100 on Android 4.2.1 Jelly Bean custom firmware. There were a few bugs previously, but almost everything works great now and you can completely experience the latest Jelly Bean, Android 4.2.1, on your Galaxy S2 I9100. You can install Android 4.2.1 Jelly Bean CM10.1 Nightly on Galaxy S2 I9100 using our tutorial below. You need to have a custom CWM recovery installed and your phone should be rooted.
In this tutorial, we will guide you how to update Galaxy S2 I9100 to Android 4.2.1 Jelly Bean CM10.1 Nightly with complete steps. This tutorial requires you to have a rooted Galaxy S2 with a custom recovery, ClockworkMod or any other recovery, installed. Don’t forget to read all the important tips given below that you have to keep in mind before proceeding to the tutorial on the next page. Make sure you also backup all your data as given since you will have to wipe everything on your phone. Let’s continue with the tutorial below.
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 (TeamAndroid.com) 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 Jelly Bean CM10.1 Nightly 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.
UPDATE: AOKP ROM based on Android 4.2.1 Jelly Bean is now available for Galaxy S2 I9100. Read the tutorial here!
Samsung Galaxy S2 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 S2 properly. If not, you can download the latest official drivers from our Android USB Drivers section here:
Download Samsung Galaxy S2 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:
- Backup your Apps. How? –> How to Backup Android Apps.
- Backup your SMS messages. How? –> How to Backup/Restore SMS Messages.
- Backup Contacts, Gmail and Google Data. How? –> Sync with Google Sync.
- Backup Call History. How? –> How to Backup Call History.
- Backup WhatsApp Messages. How? –> How to Backup/Restore WhatsApp Messages.
- Backup APN Settings: GPRS, 3G, MMS Settings. How? Note down everything from: Settings > Wireless & Networks (More…) > Mobile networks > Access Point Names.
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!
All set and ready? Good. You can now head over to the next page and install Android 4.2.1 Jelly Bean CM10.1 Nightly on your Galaxy S2 I9100.
