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Update T-Mobile Samsung Galaxy S2 T989 to Unofficial CM10 Preview Jelly Bean 4.1

There are numerous devices that are awaiting the official release of CyanogenMod 10 ROM based on Jelly Bean 4.1, but for the moment the only ROMs available are unofficial builds and you can learn how to install one of these on your Galaxy S2 T-Mobile by using the instructions that I have listed in this article.

The CM10 preview build is unofficial release by the TeamChopsticks. It is a ROM created from CM10 source code and it works with your T-Mobile variant of Galaxy S2. It brings the Jelly Bean firmware along with Google Now service, Project Butter interface improvements, offline voice recognition and multiple other similar tools. If you want to install it, you will first need to know that this is a very early preview build and it cannot be used as a day-by-day OS as it might crash at any time.

There are several functions and features that weren’t optimized for your device, which means that some of them will not work. Here’s a list with several features that are unsupported: Camera, Torch, Wi-fi tethering isn’t working if WPA is used ( use only Open mode), capacitive lights won’t work if BLN is enabled, if you enable BLN then the next time you restart it will be disabled, SMS longer that 160 characters won’t be split correctly, SMS text message sent at a small interval of time won’t be sent, the ‘Use only 2G networks’ option isn’t working, the SIM card contacts cannot be viewed, MTP mode isn’t working on Mac and Linux. If you find any more errors, then you should post them in our comments section.

Before starting to install this new ROM, you will have to read the preparation guide and you will learn that you need to create backups and multiple other tricks that will teach you how to save all your data and not lose any files because of this CM10 preview build for Galaxy S2 T989 on T-Mobile. Here’s what you need to know:

  • flash this ROM only on the Samsung Galaxy S2 smartphone on T-Mobile and with the model number SGH-T989. Do not attempt to install it on any other Android phone as it won’t work and you might brick that phone. If you don’t know where to find the model number, then open Settings, then scroll down to the ‘About phone’ option and there you’ll find the info you’re looking for.
  • the tutorial will ask you to wipe data and factory reset. This means that you will be forced to move all the important files on your device’s internal SD card as this part will not be erased. Also, you can choose to move the files on your PC to be more sure that you don’t lose them.
  • backup all installed apps, Call Logs, APN internet Settings and the SMS text messages with help from these applications: AppBAK for Android apps backup | SMS backup & restore | Call Logs backup & restore | APN Settings Backup & Restore.
  • Create a full backup of the existing ROM so that in case you don’t like how this CM10 Jelly Bean 4.1 preview custom ROM works, then you will be able to use CWM recovery and restore the working backup.
  • Your phone should be rooted and the ClockworkMod – CWM Recovery image has to be present on it.
  • Sync your Gmail with your Phone Contacts app and you will backup the saved phone numbers. These can be restored after the update to the new ROM is complete.
  • Make sure to recharge the phone’s battery so that the T989 Galaxy S2 won’t power OFF during the installation of this new ROM.
  • Enable USB Debugging option from your Android settings menu.
  • This guide and the entire post is for Android enthusiasts only and this ROM shouldn’t be used as a daily one as it contains bugs and it isn’t stable. Install it at your own risk and do not blame us in case your device is bricked in the process.

Apply all the steps listed in the tutorial and make sure that in case you cannot complete the installation, you will post in our comments section to ask for our help. This guide should be applied in no time but you shouldn’t skip any of the steps I’ve listed. Now that you know all of this, I think that you’re ready to move to the tutorial and learn how to flash the cyanogenmod10 preview ROM.

Install Unofficial CM10 Preview Jelly Bean 4.1 on T-Mobile Galaxy S2 T989

  1. Download the CM10 beta build from HERE. Save it on your PC and don’t extract its contents.
  2. Download the GApps file for Jelly Bean OS from HERE. Save it on your PC, too and don’t unzip the archived files. This file needs to be flashed flashed so that you’ll get Google Now, Play Store, Gmail and all other Google-based applications on your smartphone.
  3. Now download the modem file from HERE. This file needs to be flashed in order to force the ROM to boot and work.
  4. After you download all of the above files, you should move all of them on your smartphone’s internal SD card. Do not extract their contents.
  5. Disconnect the device from your PC and after that switch it OFF.
  6. Boot into ClockworkMod Recovery mode by holding simultaneously pressed these buttons: volume up, volume down and power. When the CWM Recovery main menu loads you will need to move to the next step.
  7. If you didn’t create a full backup of your existing ROM, then you will need to select ‘backup and restore’ and after that select ‘backup’. Wait for the process to complete. In case you have created a backup of the ROM, then you should skip this step.
  8. Select ‘install zip from sdcard’ and from the new screen select ‘choose zip from sdcard’. Find the modem zip and install it. When it’s done you should return to the main recovery menu.
  9. Now you can select ‘wipe data/ factory reset’ option and confirm this action. Move to the next step when the data wipe process is complete.
  10. Select again ‘install zip from sdcard’ and then ‘choose zip from sdcard’. Now find the ROM zip file and confirm that you wish to install it.
  11. Repeat step 10 and this time install the ‘GApps’ for JB zip file. When the ROM and the Gapps files are both installed successfully, you can return to the main recovery menu.
  12. Select ‘mounts and storage’ and then select the options that says ‘format /cache’. Confirm this process. Return to the CWM Recovery main selection menu.
  13. Now select ‘reboot system now’ option and wait until your phone will complete the first boot with this new ROM. NOTE: the first boot process of Cm10 Preview ROM will take at least 5 minutes to complete and you simply have to wait until all files are loaded.
  14. When you see the home screen you should enter your Google credentials and re-gain control over all the Jelly Bean functions and services. That’s it, you’ve successfully installed a brand new ROM on your phone.

In case the first boot process takes way too long to complete, you should remove its battery and then re-insert it back on and try again to flash all the ROM files. You should eventually manage to flash the CM10 Preview ROM on your T-Mobile Galaxy S2 T989.

For any extra questions please use the comments section. If you with to find other guides and tutorials for the Galaxy S2 T989 smartphone, then I recommend you to click the device’s name listed under this post’s photo. I think that these were the instructions that I had for you, now start testing your device and see how is CM10 Unofficial Jelly Bean ROM performing.

Also, if you don’t like how this new ROM works, then you should use CWM Recovery or ROM Manager and restore the previous ROM using the backup file you created before moving to the tutorial.