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Install CM9 RC1 ROM on AT&T Samsung Galaxy S2 I777

Galaxy S2 CM9 RC1 ROM Update

The Samsung Galaxy S2 I777 on AT&T can be updated to CyanogenMod 9 latest more stable version that has been titled ‘release candidate 1’. Use the instructions listed in this article and you will learn how to successfully flash the CM9 RC1 ROM on your phone.

This new update by CyanogenMod team can be installed only on the I777 model number of Samsung Galaxy S2 and if you’re owning on of these devices then you should use the instructions listed in this post. Make sure that before you move to the tutorial guide, you read the preparation info and learn what steps you need to take before starting to install the latest release candidate version of CM9 update.

Here’s what you need to know:

  • in the tutorial you will find a step that tells you to wipe all data and factory reset the device. This means that you should create backups of the files currently installed on you device by moving them on your phone’s internal / external sdcard or, you can choose to move them on your computer’s hard drive.
  • if you wish to backup applications, SMS, Call Logs and APN settings, then please use these Android apps:  AppBAK for Android apps backups | SMS backup & restore | Call Logs backup & restore | APN Settings Backup & Restore.
  • sync the Contacts app with the Gmail account you set for your phone and this will prevent them from being deleted. After the update is complete you should restore them back. Here’s a guide that teaches how to successfully save all the phone numbers you saved on your device.
  • install the CM9 RC1 ROM only on Galaxy S2 I777 devices that are rooted.
  • CWM Recovery should also be present on your phone.
  • enable USB debugging.
  • make sure to recharge the I777 phone battery until it reaches over 70% power levels.
  • you can create a full backup of the ROM that is currently installed on your smartphone. This should prove to be helpful in case you don’t like how CM9 RC1 is working on your device, as you can use it later to restore the working ROM installation.
  • use this guide only if you’re an advanced user and note that you are the only one that should be blamed in case your device will be bricked during the updating process.

I think that these are all the preparation steps you had to take and now you should move to the tutorial guide. Remember that in case you cannot complete the updating process, then you should use the comments field and tell us where exactly you got stuck. Make sure to read the entire tutorial before starting to apply step 1.

Install CM9 RC1 ROM on Galaxy S2 I777 AT&T model:

  1. Download the ROM zip file from here. Save the file on your PC and do not extract its contents.
  2. Download the Gapps package from here. Make sure to download the CM9-based version as other editions won’t work correctly with the ROM firmware you’re about to install.
  3. Connect your device to your PC and move both, ROM and Gapps, zip files on its internal sdcard.
  4. Next, power off the device and boot into CWM Recovery mode.
  5. When CWM Recovery mode loaded all the files you should first select ‘wipe data/ factory reset’. Confirm this action.
  6. Now select ‘install zip from sdcard’ and from the next screen select ‘choose zip from sdcard’.
  7. Find the CM9 RC1 ROM zip on your device’s internal sdcard and select it for installation.
  8. Confirm the installation of the new ROM and when you’re done you should repeat step 6, only that now you need to flash the ‘gapps’ package.
  9. After you’ve successfully flashed Gapps and the ROM zips you should return to the main recovery screen.
  10. Select ‘reboot system now’ and confirm.
  11. The AT&T Galaxy S2 will now start its first boot into CyanogenMod 9 Release Candidate 1 and you should allow it at least 10 minutes to complete the process.
  12. After the Android 4.0.4 ICS home screen loads you should set your Google account and only then you can begin to test all the CM9 RC1 ROM functions and features. That’s it, now you can use the comments section for any additional questions.

In case your device gets stuck when trying to complete the first boot, it means that it was bricked or you didn’t flash correctly the new ROM. Remember to wipe all data and only after that you should start to install the new ROM. If you get stuck and the CM9 RC1 still can’t be flashed, then you should remove the phone’s battery, re-insert it after 20 seconds and then start all over again with step 1 and now you should be able to flash all the new ICS files for your AT&T Galaxy S2 device.

Please note that this guide only works with the I777 Galaxy S2 and if you’re using a different phone then you should keep away from this ROM as it will brick that specific device. If you found this guide by mistake then please feel free to browse our website as I’m sure that you will find a helpful guide and you will manage to improve the overall performances of your Android device.