Galaxy S3 I9300 received Android 5.1.1 AOSP Lollipop Custom ROM – How To Install

Samsung’s old flagship smartphone Galaxy S3 I9300 owners have some good news that they can now experience the latest Android 5.1.1 Lollipop on their devices with AOSP custom firmware. AOSP custom ROM is popular for its performance and stability and is considered faster than the stock Android 5.1.1 Lollipop which is as close to the stock Android factory image. So if you want to update Galaxy S3 I9300 to AOSP Android 5.1.1 Lollipop custom ROM then follow the given instructions carefully.

Remember that AOSP custom firmware is developed by the third-party developers so you’ll need to have a custom recovery like TWRP or CWM in order to install the ROM .zip file on your Galaxy S3 I9300. Ready to get Android 5.1.1 AOSP custom ROM? Follow these instructions to begin the installation process.

Install AOSP Android 5.1.1 Lollipop Custom Firmware on Galaxy S3


This guide containing AOSP Android 5.1.1 custom ROM can be used for the Galaxy S3 I9300 model only. Do not try to install this firmware on any other device or incorrect variant.


AndroidBlog will not be held responsible for any kind of damage occurred to your Galaxy S3 I9300 during or after the installation of Android 5.1.1 AOSP custom ROM. Proceed at your own risk.


  • Create a proper backup of all your existing data and settings before proceeding to the installation guide using a recommended custom recovery.
  • Download and install Galaxy S3 I9300 USB Drivers on the PC.
  • Enable USB Debugging Mode on your phone by navigating to Settings > Developer Options.
  • The bootloader of your S3 should be unlocked.
  • Your Galaxy S3 should be rooted and the latest version of a custom recovery should be installed on it.
  • Make sure that the battery level of your device should be charged at least about 80%.

Required Files:

  • Download AOSP Android 5.1.1 ROM

Steps to Update Samsung Galaxy S3 I9300 to AOSP Android 5.1.1 Lollipop:

1:- First, download the AOSP Android 5.1.1 Lollipop custom ROM ( 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 AOSP Android 5.1.1 Lollipop .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 AOSP Android 5.1.1 Lollipop file to begin.

8:- After flashing the ROM 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.

That’s All! You’ve successfully installed the Android 5.1.1 AOSP Custom ROM on Galaxy S3 I9300.

Tell us in the comments section below if you are getting issues or have question regarding the above ROM installation steps.

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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