How to Update AT&T Galaxy S2 I777 to CM10 Android 4.1.1 Nightly Jelly Bean Custom Firmware

• Last modified: Android Tips

CM10 has finally started pushing the Android 4.1.1 Jelly Bean nightly updates for the Samsung AT&T Galaxy S2 SGH-I777. Earlier today, we finally got the initial nightly release for the International Galaxy S2 as well. You can now install CM10 Android 4.1.1 Nightly Jelly Bean on Galaxy S2 SGH-I777. Your phone should be rooted and ClockworkMod recovery should be installed.

In this tutorial, we will tell you how to install CM10 Android 4.1.1 Nightly Jelly Bean firmware on Galaxy S2 SGH-I777 with complete steps using CWM recovery. Make sure you backup all the data as we will have to wipe your previous personal data and apps. Let’s begin with the tutorial below.

Disclaimer: All the tools, mods or ROMs mentioned below 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 ;-)

CyanogenMod 10 (based on Android 4.1.1) Jelly Bean is still in nightly stage and will take several months before it gets matured enough to be released in a beta version. By installing this, you should remember that you may encounter bugs in the ROM after installation.

Make sure you have installed all your USB drivers for the AT&T Galaxy S2 to connect it with the computer. Download AT&T Galaxy S2 USB drivers! Apart from just the USB drivers, there are a few more things that you need to take care of.

1. You need to enable USB debugging mode. This helps to connect your Android phone with the PC. See here: How to Enable USB Debugging.

2. Your phone battery should be 80-85% charged. If your phone goes off suddenly because of battery, during flashing ROMs or installing mods and updates — your phone might go dead permanently. See here: How to Check Battery Percentage.

3. Backup all your important data that you might need as soon as your flash a new ROM, or make a backup for just in case, you never know when anything might go wrong. See below on how to backup data:

Data can also be backed up using Samsung KIES for their devices, but if you backup data manually, you get more options what top 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.

4. Your phone should be factory unlocked. Additional instructions for locked Android devices will be added in the tutorial for unlocking devices.

UPDATE: Android 4.2.1 Jelly Bean is now available for the AT&T Galaxy S2 I777. Read the tutorial here!

Now, let’s proceed with the tutorial on the next page and update Galaxy S2 SGH-I777 to CM10 Android 4.1.1 Nightly Jelly Bean custom firmware.


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  • http://twitter.com/NFLfreik Phillip Joseph

    hi great guide, flashed perfectly, just realized though that there is no “Settings>Application Settings” available, i cannot install non-market apps since there is no “allow installation of non-market apps” option…any suggestions on what to do? or will i have to wait for the update?

    • http://www.sizzledcore.com Haris Nadeem

      That same option has now moved to Settings > Security in Android 4.1.1 Jelly Bean. I hope that helps! :)

  • c.k. lester

    There are a couple of references to CM9 (“That’s it! Your AT&T Galaxy S2 should now have CM9 Android 4.0.4 ICS installed on your phone! Go to Settings > About phone to verify.”) You might want to update that when you get a chance, so as to not confuse n00bs. :-D