How To

Update LG G4 H815 to Android 6.0 Marshmallow Build 20A Flashable Stock ROM with TWRP

The latest Android 6.0 Marshmallow update is now available for the LG G4 devices as flashable ROM. Just after the release of this Marshmallow update for these devices, developers have ported the firmware file for rooted users in form of flashable .zip files that can be flashed through TWRP. Thanks to autoprime (the recognized XDA developer) for providing these flashable files taken from build version 20A that include system (stock ROM), boot, modem and bootloader zipped files which will take your LG G4 H815 variant to Android 6.0 Marshmallow without the complex process of flashing the KDZ file.

The good news is that the bootloader of your device will still be unlocked and you can easily get root access over this ROM by installing the SuperSU package later. This ROM is stock based and you might face some bugs or notifications issues with some apps. To check for possible missed notifications go to Settings> battery/energy saving> battery consumption> ignore optimization. Also, knock code has been removed but will return in a future update.

All you need to have an unlocked bootloader and TWRP (TWRP 2.8.7) should be installed on it which are required to flash the ROM files. If you have not received an OTA notification, then go ahead and follow the given guide to install stock Android Marshmallow update on LG G4 manually. Now proceed to the given instructions to update LG G4 H815 to Android 6.0 Marshmallow build 20A flashable stock ROM via TWRP.
How to update LG G4 with Android 6.0 Marshmallow Using TWRP


This guide containing the the stock flashable ROM files and instructions can be used with the G4 model H815 (international variant) only. Do not try to install this firmware on any other device or incorrect variant.


AndroidBlog will not be held liable for any kind of damage occurred to your LG G4 during or after the installation of Android 6.0 Marshmallow build 20A. Proceed at your own risk.


  • Take a proper backup of all your important data and settings before proceeding to the installation guide, in case anything goes wrong then you’ll be able to restore your data back.
  • The bootloader of your LG G4 should be unlocked in order to flash the the system and boot images. Go to the official page to unlock the bootloader.
  • Ensure that the latest version of a TWRP recovery is installed on your device. You can download TWRP 2.8.7+ build from here
  • Download and install the LG G4 USB Drivers on your PC.
  • The battery level of your LG G4 should be at least about 80% before going ahead to the installation guide.

Required Files:

Steps to Flash Stock Android 6.0 Marshmallow on LG G4:

1:- First, download the System, Modem, Boot, Bootloader zipped files from the above given links, on the desktop of your PC.

  • System :
  • Modem :
  • Boot :
  • Bootloader :

2:- Connect the LG G4 with PC using its USB data cable and transfer the downloaded files to the root folder of internal phone’s storage.

3:- Disconnect the device and turn it off in order to boot into recovery mode (TWRP).

4:- Turn on the phone while pressing and holding Volume Down + Power keys at the same time. Once the TWRP logo appears, you have successfully booted into the recovery.

5:- While the LG G4 is in TWRP recovery, perform a nandroid backup and select the System, Data, Boot, Recovery, EFS options.

6:- Navigate to the main menu of TWRP recovery and tap on the install option. Locate the ROM .zip files that you have already transferred to the internal storage of your phone earlier.

7:- Now select Modem and tap Add More Zips on the next screen and select System, Boot and Bootloader one by one.

8:- Proceed with the installation by swiping the confirmation button to install the ROM.

9:- Once the flashing process is completed successfully, reboot system.

Done! You have successfully updated LG G4 to stock Android 6.0 Marshmallow. If you have any issues or queries regarding the TWRP-flashable stock ROM then let us know in the comments area below.


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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