Unroot Samsung Galaxy S2 I9100 and install stock Android 4.1.2 Jelly Bean

Android 4.1.2 Jelly Bean now available

The Galaxy S2 users received the official update to Android 4.1.2 Jelly Bean several months ago but, since then, they have flashed new custom ROMs. This guide teaches you how to successfully unroot it and restore to stock firmware. Read the entire post and you should be able to complete the unroot process fast and easy.

In order to make sure that you successfully apply all the changes, you will first have to read the guidelines below. Here’s what you need to know:

  • Use this guide only for the Samsung Galaxy S2 model number I9100. Don’t try to use this tutorial with any other Android smartphone or tablet.
  • Your device will be restore to its stock Android 4.1.2 Jelly Bean ROM and you will lose access to any applications that require root permissions.
  • Create backups of all the data that is currently stored on your phone. This guide might remove all the files from your smartphone, which is why you have to make sure that you have copies of all your most important files.
  • The warranty of your device will be restored after you finish completing the changes.
  • Make sure that your computer has all the Samsung USB Drivers installed on it.
  • Disable any antivirus apps from running on your computer. Such programs are usually blocking ODIN and you won’t be able to complete the tutorial.
  • Make sure that your Galaxy S2 battery has enough power left before the device shuts down.
  • Enable USB Debugging from the Android Developer Options.
  • This is a guide for advanced Android users and you shouldn’t use it in case you don’t know what you’re doing. You can’t blame us in case you lose any data or you brick the phone.
  • Read the entire post first and then begin the unroot process. Don’t skip any steps that I have listed below.

Since you’ve read all of the above, it means that you can continue to the next part of this post.

How to Unroot Samsung Galaxy S2 I9100 and restore it to Android 4.1.2 Jelly Bean firwmare:

  1. Download the Firmware file from HERE. Choose whatever file you want from the list and save it on your PC. NOTE: It would be best for you download the file that corresponds to your current region.
  2. Extract the contents of the download file and you will get a .tar.md5 file. Save it on your computer and don’t extract any further.
  3. Download Odin 1.85 from HERE. Extract the zip contents and save them on your PC. ODIN is the tool you’re going to use in order to flash the new firmware files.
  4. Power off your Samsung Galaxy S2 now.
  5. Boot it into Download Mode. It can be done if you press and hold Volume Down, Home and Power buttons simultaneously.
  6. Launch ODIN program on your computer.
  7. Connect your device to your PC via USB Cable. ODIN should display a confirmation message telling you that the new device has been ‘added!!’. Get to the next step.
  8. Click the PDA button in ODIN and browse your computer for the ‘.tar.md5′ file you’ve extracted in step 2. Make sure that the ODIN Default settings are left as they are.
  9. Click the START button when you’re ready for the installation.
  10. Wait for the install to complete. This process shouldn’t take long. Your phone will reboot when all files have been installed and you can disconnect the device from your PC.
  11. ODIN will say PASS and the phone will continue to boot into normal mode.
  12. That’s it, you’ve managed to successfully restore your Galaxy S2 to stock Android 4.1.2 Jelly Bean.

These were all the steps that you had to go over and now you can enjoy your brand new stock Jelly Bean firmware operating system.

If you cannot complete the tutorial then you should ask for more help in comments, as I will try to offer you the best solutions and help you unroot your phone successfully.

In case ODIN freezes or it displays a FAIL message, then you should disconnect the Galaxy S2 from PC and remove its battery for 5 seconds. Close ODIN and then re-launch it on your PC. Next, you will need to repeat the entire tutorial starting with step 5. The tutorial should work at your second attempt.

If you don’t like the new stock Samsung-edited Android 4.1.2 JB OS and you think that you made a mistake by restoring your device to its original factory settings, then you can easily apply root using some of the guides listed at our ‘Android Root’ section here.

 

  • Ionut

    What region code does Romania have? ORO?

    • Adnan Che

      Yes but Orange provider I mean.

  • Update via internet

    Update via internet no pc

  • andrea

    The update for s2 android 4.1.2 does not function properly and the camera wont wrk. What do i do

  • vaishu

    After the update camera does not work and cannot access gallery. It keeps saying there is not enough memory and tells us to delete software and apps. Tried everything and still doesnt work. Solution please?

  • http://www.facebook.com/t1tch1 David Mc Mullen

    Update but now my phone is saying sim unlock code what is it plz

  • Samuel Scott

    Just did this, my phones been stuck doing the boot animation for like 10 minutes now. Ill leave it for some time, see if theres any change.

    • Samuel Scott

      Remained in the boot loop for another 15 minutes, then put the firmware on it again with the latest version of Odin. Still stuck in boot loop. will just get different firmware.

      • Samuel Scott

        You know what? Ill just download the EARLIEST POSSIBLE FIRMWARE for it and update it within itself.

        • hatahet

          my phone got stuck too :| did it work with earlier firmware
          !?

  • eki

    If you have a reboot loop. You should wipe your cache. You get to menu with pressing volume up+menu+power keys simultaneously.

  • Calin Uioreanu

    view the source of the samsung-updates file in order to chose the right archive.

    secondly, I had to wipe out the /data/ partition before the actual ODIN installation (by pressing Volume UP + POWER + HOME), otherwise the S logo appeared to load forever with two different firmware.

  • Nilesh

    I had just rooted a custom kernel and am on stock ROM. I want to unroot back. Help me. Will I loose data?

  • Nilesh

    warranty will not be restored. My custom kernel count shows 1 even after doing this method

  • Sparsh

    I cannot find the region code for Thailand please help!

    • Sparsh

      never mind i just found it sorry!