Update Samsung Galaxy S2 GT I9100 to Official Jelly Bean 4.1.2 UHMS9 firmware

For Samsung Galaxy S2 GT,  I9100 model has been released in OTA the new Android Jelly Bean 4.1.2 OTA update.  If you don’t receive this last Android 4.1 stock update in the OTA, then if you want to improve your S2 device with the same you should install this update manually. This article will teach you a step by step tutorial about how to install the official Android 4.1.2 Jelly Bean firmware (UHMS9) on the Galaxy S2 GT I9100 device.

This latest update released by Samsung for S2 GT I9100 doesn’t come with big changes in the trend of features but comes to resolve the previously reported bugs.

This UHMS9 latest update, is a more stable version of the JB 4.1.2 OS for your Samsung Galaxy device and you’ll be able enjoy updates for a few several based applications and programs that you using constantly.

This update can be installed only for the unlocked Samsung S2 I9100 devices, but except Hong Kong, Taiwan and China; you can install the Android Jelly Bean 4.1.2 can be install OTA or using Kies app for your device or you can flash it manually. So this present article will show you a step by step tutorial about how to install this update manually on your S2 device.

This manual installation for the latest official Android 4.1.2 OS can be applied for the S2 owners that have a rooted smartphone, the OTA procedure isn’t supported by the smartphones that have an unlocked and rooted OS. To conclude, if you running in your device a custom ROM firmware, then this guide is necessary if you want to update your device.

If your device’s warranty was voided, when you’ve installed the custom ROM then you’ll be able to restore it, but you’ll lose the root rights and the unlocking bootloader will be revoked.

Before to starting the updating tutorial, you need to follow some prerequisites that are required to be followed before to apply the firmware update, be sure to follow all these prerequisites and all the guide steps in the correct order because you’ll have to use Odin software and if something isn’t made correctly you can brick your device or you cannot install the JB 4.1.2 UHMS9 ROM in your S2 GT I9100 device from Samsung.

The prerequisites are:

  • This tutorial and all the instructions listed here are compatible and can be applied only with the Samsung Galaxy S2 model number GT I9100. So, don’t apply the same for any other device you can easily brick them.
  • You’ll need your smartphone, original USB cable and a windows PC based near of you, you will use these during the tutorial.
  • Deactivate or uninstall all the security applications and the settings which can interrupting the flashing process or can interfering with Odin, so turn off the antivirus and the firewall apps protections on both devices, your S2 and on PC.
  • Backup all your Samsung Galaxy S2 data store in the internal device’s memory, before to proceed the flashing new ROM OS data like SMS, contacts, call logs, applications, EFS, any images files and videos files, documents and so on.
  • If you’ve installed a custom Recovery image, make a Nandroid backup for your actual running ROM.
  • Download the Samsung KIES on your PC, and install the compatible drivers for your Samsung Galaxy S2 device;
  • From your S2 menu go to Settings -> Applications -> Development -> USB debugging and enable the USB debugging option.
  • Verify your device’s battery and be sure you have more than 70 % power left to be sure that your device won’t take a forced shutdown in the middle of the flashing process; it might damage or brick your device.
  • Be sure you read all the instructions and all the steps and you’ll apply in the correct order.
  • This article and all instructions listed here are only for educational or instructional purpose, and we cannot be blame or held responsible for what can happens in your proper circumstance, is your decision if you want to apply the same, and all the risk is yours.

How to Update Galaxy S2 GT I9100 to Official Jelly Bean 4.1.2 UHMS9 OS

  1. Firstly, download the JB 4.1.2 UHMS9 ROM update file from here and save it in your Computer.
  2.  Secondly, download the Odin application and save it in your PC
  3. Now, extract the downloaded update file on your PC and install the Odin software.
  4. Open the Odin app.
  5. Turn off the S2 smartphone.
  6.  Reboot the Samsung Galaxy S2 device into download mode. To do this, you’ll need to press on Volume Down, Center and Power buttons simultaneously.
  7.  Now, when your device is in Download mode, connect the smartphone to the PC using the original USB cord.
  8.  On Odin software verify if the ID:COM section is yellow or blue and the “added” message is showed. Note:In case these settings are not like above you need to close the Odin application, disconnect the smartphone from the PC be removing the USB cord and after that re-install the S2 proper drivers on the PC. After you made this repeat the steps.
  9.  From the ODIN’s app interface select “PDA” option and search and pick the.tar file.
  10.  If there are more files on the extracted downloaded folder package click on: “CSC” and load the CSC file; on “PHONE” field search and pick the Modem file; on the “PIT” field search and pick the .pit file.
  11.  Now after you pick all the updating package files click on “Start” from the ODIN and wait to installing the latest Android 4.1.2 UHMS9 OS on your Samsung Galaxy S2 device.
  12. When the flashing process is done on the Odin app one “pass” message will be showed.
  13.  Now, disconnect the S2 device from the PC
  14. Reboot your smartphone.

Note: If during the flashing process you’ll cannot apply the procedure, and the Odin get stuck, then you have to: close the Odin software and after that to disconnect your device by removing the USB cord, restart your Samsung Galaxy S2 device with a forced restart, and then you should to re-install the proper drivers. Now, repeat the procedure from the starting point.

After you finished the procedure and your device at the first boot will get a boot loop, you have to: stop your smartphone with a power off, after that reboot it into the recovery mode and from there select “wipe data factory reset” & “wipe cache partition” after you wipe the data select “+++go back+++” and in final select “reboot system now”.

That’s all steps that you need to follow in order to successfully complete updating your Samsung Galaxy S2 GT I9100 with the latest official Android 4.1.2 Jelly Bean UHMS9 OS firmware.
After you entering in the new Android 4.1.2 version on your S2, let us know about its performances, and share with us your impressions in our comment section.

  • dhonz

    just for Telcel network

    • Robert Schwenk

      any solutions to the network problem?

  • bufz

    i have a Unlock Network issue

  • jens

    same prob here -.-

  • shelesh

    please suggest how to unlock network issue with completed steps

    • Robert Schwenk

      any solution to the network problem?

  • Bangra

    what if mine is not a genuine samsung os 4.1.2 and i want to change it to genuine samsung os… to know this when i connect my s2 to my pc and when i open kiesair, on the firmware information it shows “Your devices’s current firmware version is not supported to update firmware via kies.”

  • Robert Schwenk

    I successfully updated my i9100 to Jelly Bean 4.1.2 and it looks fantastic HOWEVER the phone down NOT give me an option to enter an unlock code. What can I do. I’ve attempted various steps from the phone dialer screen but I repeatedly get a “Not registered on a network” message. Please HELP!