How to Root AT&T Samsung Galaxy S2 SGH-I777 on Android 4.1.2 Jelly Bean Firmware I777UCMD8

Android 4.1.2 Jelly Bean update finally arrived on AT&T Samsung Galaxy S2 SGH-I777. With latest Jelly Bean installed on Galaxy S2, your phone is now transformed into a brand new smartphone with lot of exclusive Jelly Bean goodies installed. If you still wondering how to update to latest Jelly Bean firmware, here is the complete guide for you to update to I777UCMD8 firmware and proven working by our reader. Thumb Up!

At the same time, while you are busy testing all of this feature, we try to make you even more excited with working tutorial to root your device. Fear not, it is what you need to unleash the full features on your device without the restriction from the carrier.

In order to avoid any trouble during the rooting process, we highly recommend you to read the pre-requisite and requirements section and do exactly what is told. This might helps to reduce the cases whereby your device is bricked because of a wrong step or you did not follow the steps. If you are facing any problem preparing your device, you are welcomed to drop us a message.

We always prepare the easier tutorial for you to root Galaxy S2 without any hesitation. If you in doubt of any single step in this tutorial, please stop and ask. From here, we ask for your favour to feedback to us if this tutorial is working or not working. We shall update to make sure this guide works for you.

How To Root AT&T Samsung Galaxy S2 SGH-I777 on Android 4.1.2 Jelly Bean Firmware I777UCMD8

Disclaimer: It’s always a risk to modify your device. We, Android Teen are not responsible for any damage or bricks on your device. Your device warranty may void with any mod. Check your devices warranty’s term & conditions before start.(HTC,Samsung,LG, Sony, Motorola). Use this guide on your own risk, contact us for help if you face problem.

Pre-requisites & Requirements

  1. Samsung Galaxy S2 –  AT&T SGH-I777 (Ensure correct device model and firmware; Check device model – Go to Settings -> About Device -> Model Number)
  2. Windows-based computer or laptop
  3. Download Samsung Galaxy S2 USB driver for Windows and install in your computer.
  4. Connect device to computer with USB cable to complete installation.
  5. Skip this step if you have installed the USB driver.
  6. Enable USB Debugging on your device. How to Enable USB Debugging Mode on Android Devices.
  7. Make sure your phone is charged to 60% 80% to avoid battery blackout and interruption during this tutorial.
  8. We recommend you make a backup on your data and media files before the tutorial. You may restore the data and files if necessary.

Reminder: Ensure you make a backup before proceed. Besides that, ensure you meet the requirements before proceed. Contact us if you face problem.


  1. Framaroot (framaroot-1.4.2.apk | 2.16 MB) – Source


  1. Browse this webpage using your device.
  2. Download Framaroot apk file into your device.
  3. Go to Menu—>Download, locate the Frameroot apk file.
  4. Press on Frameroot apk file in the Download folder. A pop-out windows ask for confirmation, press confirm/yes to proceed with Framaroot installation.
  5. Once Framaroot successfully installed on your device, you shall find Framaroot icon in the Menu.
  6. Press on Framaroot icon in Menu to launch the app.
  7. In Framaroot user interface, choose Aragorn exploits within the list of exploits.
  8. You shall now receive a exploit results: “Success … Superuser and su binary installed. You have to reboot your device”
  9. If you receive any of the following exploit results, please consult us.
    • “Failed … Exploit work but installation of Superuser and su binary have failed”
    • “Half-Success :-/ … system partition is read-only, use local.prop trick. Reboot your device and use adb to see if it run as root”, happen when the filesystem in use on system partition is a read only filesystem (ex: squashfs)
    • “Failed … Try another exploit if available”
  10. After the process completes, you may reboot your device.
  11. Download root checker to check your root status.

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A 17 years old young tech enthusiast who loves Android and smartphone. He love to learn and share Android latest technologies to public users. He likes to play around with custom ROM flashing, customize theme, system tweaking and discussion with other developers on Android development. Now, he owns Galaxy S3, LG Optimus L5, Sony Xperia Z and pre-owned Sony Xperia P, HTC One X, LG Optimus G.
  • Vester

    This doesn’t work the application will fail on AT&T S3 4.1.2!!!

    • androidteen

      Vester, please see the title carefully. This is for Galaxy S2 not S3!

      • Vester

        Oh, sorry. I didn’t notice and assumed it was for s3 since it was for 4.1.2.

  • laaaymo

    soooooo im kinda new to this but when i rooted and everything it said it was successful and yet when i got to update my device (after flashing it) i keep getting some failure to verify whole signature error. i don’t know what is wrong with it and i wasnt able to find much information on the matter. plz help.

  • laaaymo

    hmmm maybe its because my phone isnt on 4.-anything jellybean. im still running 2.3.6.

    • androidteen

      laaaymo, this is root guide for Galaxy S2 running Jelly Bean I777UCMD8 firmware. Do not try to root your phone if you have different firmware installed in your device.

  • Christian Owens

    Uhm, why is my phone saying I can’t open the file?

    • androidteen

      May I know which file you mention?

  • jholgate

    Samsung SGH-i777



    se.infra@SEP-126 #3
    SMP PPREEMPT Tue Apr 23 22:10:17
    KST 2013


    Downloaded (via my phone) Framaroot 1.4.2 APK. Error “Cannot Open File” (tried 1.4.3 too. Same deal.) Any ideas?

  • georgetownlax17

    Do i download framaroot on my phone directly or through the computer to the phone?

    • androidteen

      Downloaded into your device directly is the faster way.

  • hello

    WOW! ok every comment ive seen that had a problem didnt have the correct
    android version (4.1.2)…but if you do and you read the instructions
    carefully, it is the simplest method ive ever seen! theres an option to
    root, and unroot as simple as 1 click!

    BTW you can eaily upgrade to 4.1.2 using Kies.. just search for it
    CHEERS! i owe you one 🙂

  • Savagesm

    Downloaded and installed received the success message. However Rootchecker say’s “sorry! This device does not have proper root access.” what should I do now?

    • Savagesm

      Nevermind figured it out.

  • Carlos

    I have some doubt’s, sorry if are a kinda stupid, i am a newbie at this…

    1.- Shouldn’t i use Odin for this? I’ve seen a lot of people use that and is weird that i don’t need to do that in this method.

    2.- Does it matter the kernel or the complitation number of my phone?

    3.- If the failed message apear, what should someone do?

    AND the most important one… Should i have the phone off or on .(if it’s on do i have to do it in usb mass storage?)