Update Galaxy S3 I9300 to Android 4.1.1 Jelly Bean with ROMOW Extreme ROM [How to Install]
Photo: XDA Developers

Android users often flock to custom ROM updates to enjoy a refreshing new look on their device. Besides, there are power hungry users who crave for an improved performance alongside longer battery life on their Android smartphones and tablets. The massive base of Android community of users also includes novice users who are eager to taste the latest software update ahead of its official release on their phones.

Galaxy S3 users can now enjoy aesthetics, performance and latest Android features in one neat package, thanks to the release of ROMOW Extreme ROM based Jelly Bean update by XDA Developers member - mowow. Samsung S3 users will not only get the latest Jelly Bean update, but the ROM also brings a host of goodies such as BusyBox, Superuser, and optimisations for improved battery life and performance. In addition, you get to relish a bloatware-free browsing experience with the inclusion of an enhanced Task Manager, an extended Power menu and a lot more other features.

Key Points to Note

  • The ROMOW Extreme ROM and the instructions provided in this guide are compatible with the international variant, Samsung Galaxy S3 I9300 model only. It will not work with any other device. Verify your device's model number by navigating to Settings > About Phone.
  • IBTimes UK advises users to backup apps, important personal data and settings to prevent unexpected data loss while flashing the Romow custom ROM or installing the Jelly Bean update.
  • 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 using the Android 4.1.1 firmware update. Users are cautioned to proceed at their own risk.


  • Ensure that your Galaxy S3 smartphone is rooted with ClockworkMod (CWM) recovery installed on it.
  • Download the ROMOW EXTREME ROM (ROMOW EXTREME by mowmo.zip, 550.0 MB) to your computer.
  • Verify that your phone's battery is at least 85 percent charged to avoid unexpected device shutdown (due to battery drain) while flashing the ROMOW Extreme ROM or installing the mods and updates.
  • Enable USB debugging mode by navigating to Settings > Application > Development. This feature helps in connecting your Android phone with the computer.

How to Update Galaxy S3 I9300 to Android 4.1.1 Jelly Bean with Romow Extreme ROM

Step 1: Copy the ROMOW Extreme ROM file that you downloaded, to the root folder on your Galaxy S3â€ēs internal SD card.

Step 2: Power off your phone.

Step 3: Now, press and hold down the Volume Up, Home, and Power buttons, until the phone boots into CWM Recovery Mode.

Step 4: In CWM Recovery, perform a NANDroid Backup by tapping Backup and Restore and then hit Backup.

Step 5: Tap Wipe Data/Factory Reset and confirm the action on next screen.

Step 6: Hit Wipe Cache and confirm it on next screen.

Step 7: Choose Advanced and click Wipe Dalvik Cache.

Step 8: Choose Install ZIP from SD card.

Step 9: Tap Choose ZIP from SD card and choose the ROMOW ROM file. Now, the ROM installation should begin.

Step 10: Hit Go Back and click Reboot System Now.

The ROMOW Extreme ROM based Jelly Bean update is now successfully installed on your Samsung Galaxy S3 I9300.

[Source: Android Authority]