Galaxy S3 I9300
Install Android 4.2.1 Jelly Bean on Galaxy S3 I9300 with Official CyanogenMod 10.1 ROM .

Samsung Galaxy S3 I9300 users can now enjoy the official build of CyanogenMod 10.1 ROM (CM10.1) for Android 4.2.1 Jelly Bean update, with due credit to the industrious CyanogenMod Team. Earlier, the company's flagship smartphone received the unofficial build of CM10.1 ROM with a few untested bugs and broken features.

The official version of CM10.1 brings a high degree of customisation that is lacking on stock ROMs, besides porting a plethora of exciting features such as multi-user support, gesture typing, new quick settings option, lock-screen widget, new camera app, photo sphere, improved Google Now, new daydream feature and miracast display onboard.

The CM10.1 ROM is a nightly build and hence it may harbour a few untested bugs or broken features. The issues are expected to be fixed in the upcoming updates, as part of the development progress.

Key Points to Note

  • The official CM10.1 ROM and the instructions given in this guide are applicable to the international variant - Galaxy S3 I9300 model only. It will not work on any other device. Verify your device's model number by navigating to Settings > About Phone.
  • IBTimes UK advises users to back up apps, important data and settings to prevent data loss while flashing the official CM10.1 ROM on the Galaxy S3 I9300.
  • Verify that your phone has at least 80 percent battery charge to avoid unexpected device shutdown (due to battery drain) while installing the official CM10.1 ROM on your Galaxy S3.
  • Make sure that the correct USB drivers are installed for your Galaxy S3 on the computer (download USB drivers).
  • Ensure that USB Debugging mode is enabled on your phone by navigating to Settings > Applications > Development.
  • Make sure that the device is rooted with ClockworkMod Recovery installed on it.
  • Flashing this ROM on your Galaxy S3 will increase its binary flash counter and also void its warranty.
  • The instructions provided in this guide are meant for reference purpose only and do not cover any warranty claims involving device damage or issues arising out of installing the latest Android 4.2.1 Jelly Bean firmware.


Download official CM10.1 Android 4.2.1 Jelly Bean ROM for Galaxy S3 I9300

Download Google Apps (GApps)

How to Install Android 4.2.1 Jelly Bean on Galaxy S3 I9300 with CM10.1 ROM

1. Connect your phone to the computer with original USB cable.

2. Copy downloaded ROM and Google Apps zip files to the root folder of your phone's SD card. Important: Do not extract any files.

3. Disconnect USB cable from the computer and power off your phone.

4. Boot into recovery mode. To do so, press and hold Volume Up, Home and Power buttons together until the screen flashes, and then release all buttons. NOTE: Use volume buttons to scroll and Power button to select an option in recovery.

5. Take a Nandroid backup of your current ROM so that it can restored later if something goes wrong with the new ROM. To do a backup, choose Backup and Restore and then hit Backup again on next screen. Return to main recovery menu once backup is done.

6. Perform a full data wipe process. To do so, choose Wipe data/factory reset, then hit Yes on next screen to confirm. Wait for a few minutes until the data wipe process completes.

7. Choose

8. Once ROM is installed, repeat step 7 but choose GApps file instead of ROM to install Google apps package.

9. When Google Apps is installed, return to main recovery menu and tap Reboot System Now to reboot the phone into Android 4.2.1 Jelly Bean based CM10.1 ROM. The first boot may take about 5 minutes. So, leave it alone.

10. Restoring Previous ROM: To restore your previous ROM, boot into recovery, choose Backup and Restore then restore your previous ROM by selecting it from the list.

Android 4.2.1 Jelly Bean based official CM10.1 ROM is now installed and running on your Samsung Galaxy S3 I9300. Go to Settings > About phone to verify the firmware version installed.

[Source: Android Jinn]