We’ve just received news that another unofficial custom ROM is now available and this time it’s for the LG G3 D855. The new custom ROM is based on Android 5.1 Lollipop CyanogenMod 12.1. If you are familiar with the LG G3, the company has recently released Android 5.0 Lollipop update for it, but, if you want to try out the latest Android 5.1 Lollipop update then you need to install this ROM. The ROM is currently in development so you may expect some minor bugs which will be fixed in the coming updates.


Before proceeding, let me remind our readers that this ROM is a custom ROM and it’s not officially released by LG. So, if you are ready and good to go, then you need to follow the steps below on how you can install CyanogenMod 12.1 Android 5.1 Lollipop on LG G3 D8555.


  • Before proceeding, make sure you have properly taken the backup of your important data including personal photos and videos.
  • Your device should have more than 60 percent battery to prevent any unexpected shutdowns during the process.
  • You have installed the LG G3 USB drivers on your PC.
  • Your device must be rooted and have Custom Recovery like CWM installed.
  • You should have enabled the USB debugging mode. If you not then go to settings > Developer Options and enable it.
  • This guide is only for LG G3 D855 . Don’t try it on other Android devices.

How to Install CyanogenMod 12.1 Unofficial ROM for LG G3 D855:

Step No 1:- First of all, download the CyanogenMod 12.1 ROM for LG G3 D855 and Google Apps.zip files on the PC.

Step No 2:– Connect your device to the PC via USB data cable and mount its USB memory storage.

Step No 3:- Copy the CyanogenMod 12.1 ROM .zip file which you’ve already downloaded from the above link, to the root folder of your SD card.

Step No 4:- Disconnect the LG G3 from the PC and power it OFF in order to boot into Recovery Mode.

Step No 5: Turn On the device while pressing and holding Volume Down + Power keys at the same time until the LG logo appears. Release the buttons and press them again. Now press power keys 3 times to boot into recovery mode.

Step No 6:- The device is now in TWRP recovery, now create a Nandroid backup.

  • Select Backup
    Do a swipe on the Swipe to Back Up option.

Step No 7:– Next, perform a full wipe including Dalvik Cache, Cache, System and Factory Data Reset.

Step No 8:- Once done, go back to the main menu of Recovery and select Install.

Step No 9:- Navigate to the unofficial CM12.1 ROM .zip file that you’ve already transferred to the root folder of SD cart. Select it and swipe the Swipe to Confirm Flash option to begin the installation process.

Step No 10:- Go back to the main recovery menu and select Reboot > System after the installation is completed.

Step No 11:- Now, install Google Apps on your LG G3 by repeating the above steps.

Step No 12:- Reboot the LG G3.

That’s it. Your device has been updated to Android 5.1 Lollipop via CM 12.1 ROM . Now Go to Settings > About Phone to verify the Android version. If you have any questions let us know in the comments.


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