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Install Dirty Unicorn Android 5.1.1 Lollipop Custom ROM on Galaxy S3 I9300

A new Dirty Unicorn custom ROM based on Android 5.1.1 Lollipop can be flashed on the Galaxy S3 I9300. So if you have Samsung’s 2012 flagship Galaxy S3 then you can now experience the latest Android OS build version and its exclusive features by installing this custom ROM. Dirty Unicorn ROM comes with a lot of custom features, thus you can easily modify your S3 as per your demand. The size of this ROM is 197MB, many users reported that its a stable ROM with no major bugs. Go ahead and follow the given step-by-step guide to optimize the performance and extend the battery life of your Galaxy S3.

Please note that Dirty Unicorn custom ROM is not officially released by Samsung, thus you will need a custom recovery like CWM or TWRP in order to install the firmware and Google Apps .zip files on your device.

Get Android 5.1.1 Dirty Unicorns Lollipop Custom ROM on Galaxy S3 I9300


This guide containing the Dirty Unicorn custom ROM based on Android 5.1.1 Lollipop is compatible with Galaxy S3 GT-I9300 (with Exynos chipset). Do not try to install this firmware on any other device or incorrect variants. Verify the model number of your phone by navigating to Settings > About phone > Model Number.


AndroidBlog will not be held responsible for any kind of damage occurred to your Galaxy S3 during or after the installation of Dirty Unicorn custom ROM based on Android 5.1.1 Lollipop. Proceed at your own risk.


  • Take a proper backup of all your important data before proceeding to installation guide via custom recovery such as CWM or TWRP recovery. In case anything goes wrong then you’ll be able to restore the data on your phone.
  • Enable USB Debugging Mode on your Galaxy S3 I9300 by navigating to Settings > Developer Options and check USB Debugging option.
    • Note: Please note that if the “Developer Options” is not available in Settings, then go to “About Phone” options in Settings and find the Build number there. Tap on the Build number for 7 times and the Developer Options will be appeared.
  • Verify the battery level of your Galaxy S3 I9300, it should be above 80% before proceeding to the installation instructions.
  • Download and install Samsung USB Drivers for Galaxy S3 I9300 on the PC.
  • Your Galaxy Galaxy S3 I9300 should be rooted.
  • The device have a custom recovery (CWM/TWRP) already installed.

Required Files:

Steps to Install Dirty Unicorn Android 5.1.1 Lollipop custom ROM on Galaxy S3 GT-I9300:

1:- First, download the Dirty Unicorn Android 5.1.1 Lollipop custom ROM ( and Google Apps package from the above links on the desktop of your PC.

2:- Now connect your Galaxy S3 to PC using its USB data cable and mount the Memory Storage of the phone.

3:- Copy/paste the Android 5.1.1 Dirty Unicorn ROM .zip file to the root folder of your SD Card on the phone.

4:- Disconnect the device from the PC and turn it off in order to boot into Recovery Mode.

5:- Turn on the phone by pressing and holding Volume Up + Home + Power keys at the same time for a few seconds.

6:- While your device is now recovery mode, perform a full data wipe by selecting wipe data/factory reset, wipe cache partition and wipe dalvik cache.

Note:- Wipe Dalvik Cache will help you to prevent boot loops and issues related to ROM while installation.

7:- Next, navigate to the main menu of Recovery and choose install zip from sdcard > choose zip from sdcard. Find the ROM .zip file that you’ve already transferred to the SD Card of your phone in Step No 3. Just select it and confirm the installation of Dirty Unicorn ROM file to begin.

8:- Once the ROM installation is finished, install the Google Apps package by repeating the above procedure on your Galaxy S3.

9:- After flashing the ROM and Gapps .zip files on the phone successfully, reboot it by selecting reboot system now.

Your device may take some time to boot for the first time after the installation. So be patient and wait for the process to be completed.

Done! You’ve successfully installed the Android 5.1.1 Dirty Unicorn Custom ROM on Galaxy S3.

Let us know in the comments section below if you have any trouble or query while flashing Dirty Unicorn ROM featuring Android 5.1.1 on your Galaxy S3 I9300.


Aamir Jamal

An Android Geek and audiophile who love to read and write reviews/tutorials about gadgets and new tech stuff. He has written 1007 guides and other posts.

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