(Last Updated On: July 25, 2015)

Android 5.1.1 Lollipop has done a great job in all aspects, whether it’s the user-interface or the features. Google made this OS more secure also which makes this OS less venerable to any theft. Google introduced a design called material design in this version of Android and everyone is loving it. Today I’m going to tell you about CM 12.1 ROM for your AT&T LG G3. The aforementioned CyanogenMod custom ROM has all the features of Android 5.1.1 lollipop with some bonus features like tweaking the performance or interface. So get ready to install this ROM on your phone after the drop.

CyanogenMod brick

  • Installing a custom ROM is an unofficial process which may void your AT&T phone’s warranty.
  • Backup all of your important data before installing ROM on your phone.
  • You need a PC, a USB cable and your phone rooted and custom recovery installed.
  • To boot your phone into recovery you need to turn your phone off and turn it on by pressing and holding volume up and power key together and when you see LG key leave the keys and press and hold them again.
  • Charge your phone to at least 50% of battery so it will get through the installation process without getting off.
  • Install this ROM only on a rooted AT&T LG G3, do not try to install it on any other Android device.

Steps to install CM 12.1 Nightly ROM on AT&T LG G3:

  1. First you need to download this CM 12.1 Android 5.1.1 ROM zip file and save it on your PC, do not unzip it we have to use it as it is.
  2. Now download the Google Gapps package zip file from this page and save it to your PC.
  3. Connect your phone to your PC as mass storage and move those zip files to your phone’s SD card.
  4. Unplug your phone from PC and shut it down.
  5. Boot your phone to recovery mode as is told you before in this article.
  6. In recovery first take a backup of earlier ROM, tap on “backup” then confirm this step to back up your previously installed ROM.
  7. Now tap on “wipe” and confirm the step to wipe the data and cache.
  8. After that, tap on “install” and choose the ROM zip file and confirm the step to install this ROM on your phone.
  9. Now do the above step again with the Google apps zip file and after that tap on “reboot” and select “system” after that.

Wait for about 10 to 12 minutes to get to the welcome screen and complete the setup to take over your phone again. Furthermore, if you have any query about this ROM or installation process, then you can post your queries in the comment section below.