Last Updated on April 1, 2017 by Mathew Diekhake

These are the instructions for installing XenonHD Android 5.1.1 Lollipop ROM on the AT&T variant of the LG G3. To install a custom ROM you first must have a custom recovery installed. The XenonHD custom ROM is great for updating the LG G3 to the latest software update available — the Android 5.1.1 Lollipop. You cannot update to Android 5.1.1 from official software updates since the OEM and phone carrier networks have not yet released them . With Android 6.0 Marshmallow’s release just around the corner. Nobody knows if the 5.1.1 Lollipop will eventually roll out to the G3 handsets or not. Therefore, updating to the latest Lollipop using this custom ROM is the best idea.

LG G3

The Files You Need

  • Download the XenonHD 5.1.1 ROM file from here.
  • Download the Google Apps for Android 5.1.1 from this page.
  • The guide is only for the G3 with model number D850 by AT&T. You can anytime check your G3 model number by heading to the Settings > About Device > looking at the model number.

Installing XenonHD Android 5.1.1 Lollipop custom ROM on the LG G3 by AT&T

  1. Down load both the Google Gapps and the XenonHD ROM to the desktop of the computer — it can be any computer.
  2. Connect the G3 by AT&T to the same computer where you have the files. Do not unzip the files, we are transferring them as is.
  3. transfer the two files to the SD card — that’s the internal storage on the device.
  4. Unplug the Lg G3 from the computer.
  5. Reboot the G3 from AT&T into the custom recovery mode that you have installed. You’ll need to start by turning off the smartphone if you are using the key combination. Otherwise, you can download the Quick Boot app from the Google Play Store.
  6. Once you are in the recovery mode, the wording can vary depending on the exact recovery you are using.
  7. Make sure you take a NANdroid backup before wiping the current data and ROM clean. Take the NANdroid backup now.
  8. Navigate to the ‘wipe’ or ‘wipe data/factory reset’ option in the recovery.
  9. Navigate to the ‘Install’ option from the main recovery menu.
  10. Browse the SD card for the XenonHD ROM file and install the ROM.
  11. Browse the SD card again and upload the Google Gapps package and install the apps.
  12. You now have the custom ROM installed on your device and the stock Google Apps ready to load. All you need to do now is reboot the smartphone.
  13. To do that, go back to the main recovery menu and use the ‘reboot system’ option from the recovery menu.