Android 5.1.1 Lollipop has many great features to make your Samsung Galaxy S3 phone looks beautiful and more secure than ever. Android 5.1.1 Lollipop has the Material Design even in all the apps to make it more beautiful and the most simple interface ever built in any mobile OS. The later stages of Android Lollipop also has some security options like password on recovery. This custom ROM also has all the features mentioned above with some extra custom actions to customize your mobile experience. You can customize the interface the way you like, also you can boost performance to an amazing level. Follow the guide carefully and install this unofficial S3 custom ROM on your phone successfully.
Rooting or installing a custom ROM on some devices may lead to a violation of the warranty for that device. If your phone is included in this list, then you should be responsible for any damage or voided warranty.
Keep your data safe by making a backup of it to your PC because installing the custom ROM. It will erase all the data stored on your internal memory. Contacts and messages will also get deleted, so save them by syncing them to your Google account or backup them using any backup making app from Google play store. Also backup your media files to your P or any other external drive.
You need a PC with internet connection, a USB cable and your phone rooted and a custom recovery installed on it (TWRP is recommended in this guide). Plug your phone to your wall charger and charge it to at least 70% battery level.
The guide and installation files are only for AT&T Samsung Galaxy S3 SGH I747 only. Do not try to install this on any other Android variant or it will damage your device.
Steps to install custom on AT&T Samsung Galaxy S3 SGH I747:
- First you need to download the CM 12.1 custom ROM zip file to your PC and save it on desktop.
- Download the appropriate G apps zip file to your PC and also save it to your desktop.
- Now plug your phone to your PC and transfer these two zip files to your phone.
- Unplug your phone and turn it off completely.
- Turn it on to recovery mode by pressing and holding Volume up key, power key and home key together.
- In recovery mode tap on backup > confirm the step to back up your previous ROM.
- After that come back to the main menu and tap on “Wipe” then confirm the step to wipe the internal memory.
- Finally tap on “install”, select the ROM zip file and confirm the step to begin the installation process.
- When installation’s done, repeat the 8th step with G apps zip file to install Google apps on your phone.
Tap on “reboot” then “system” to reboot your phone to OS mode. Wait for some time and you will see a welcome screen and you know what to do after it.