LG has started to roll out Android 6.0 Marshmallow update for its last year flagship LG G3. Currently the update (build number 30B) is available for LG G3 D855 variant and update for other variants are imminent. LG’s current flagship G4 has already updated to Android 6.0 Marshmallow.

LG G3 (D855) owners will receive the Android 6.0 Marshmallow update via OTA (over-the-air). However, tech savvy users who cannot wait for the OTA can install the update manually right now by downloading the official firmware (KDZ file) and using the LG Flash Tool.



Android 6.0 Marshmallow update brings performance enhancements, better battery life via Doze mode, and a number of new features like personalized app permission to LG G3. Interested users may follow the guide below to know how to flash the stock firmware manually on LG G3.

Install Android 6.0 Marshmallow update on LG G3 D855 Using LG Flashtool


a) Install LG USB drivers on your computer (Windows); otherwise, your device will not be able to recognize your phone.
b) Your LG G3 should be updated to latest version of Android Lollipop

Disclaimer: Follow the instruction at your own risk. We will not be liable if any damage occurs to your device and/or its components. It is recommended for technically talented users only. Backup every data on your phone.

1. Download stock .kdz firmware file for LG G3 D855 [HERE]. The file extension should be .kdz.

2. Download LG Flashtool [HERE] and unzip it in a folder. Double click the ‘LGFlashTool2014.exe’ file to run it.

3. Now, boot your LG G4 into download mode. To do so, switch off the phone, then press the Volume up button. While pressing the Volume button, connect the phone to a USB cable. You should see ‘Firmware Update’ dialogue on the screen.

4. Now, on LG Flashtool, click the browse button, select the .kdz firmware file and then click ‘Normal Flash‘ if you are on LG stock firmware, click ‘CSE Flash’ if you are on custom ROM to flash the .kdz firmware on your LG G3.

5. You will get a ‘read phone information’ window as shown below. Just click the ‘Start’ button and proceed.

6. If asked for administrator permissions, just accept it.

7. You will now see ‘Select Country & Language’ window. Select ‘Different’ from the country list, then select ‘English’ from the language list [DO NOT tick the Smartphone upgrade check box] and then click ‘OK’ to start flashing firmware.


8. Once the progress bar reaches 100%, you will get ‘Connection to server failed’ error. This is normal, so do not disconnect your phone. Wait until you get ‘COM’ written in green text on your phone.

9. Once you get ‘COM’ written in green text on your phone screen, click OK to the “Connection to server failed” error.

10. Once the firmware flashing completed, your phone will reboot automatically.

Note that, the first boot will take more time than usual , so be patient. Once booted up enjoy Android 6.0 Marshmallow on your G3 (source – XDA)

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Kannan is a computer and Android enthusiast, a blogger by passion and a tech freak. His always ready-to-help attitude, knowledge and hard work is what drives him.


  1. Hi I am using d 855 kitkat version whenever i try to update it, It says that you are using the latest version of os. Kindly help me

  2. Can anyone help me?

    I am using Lg G3 D855 international version(32gb).I updated it from android 5.0 lollipop to 6.0 marshmallow manually by using .kdz file through lg flash tool and my update completes 100% without any error and after my update I factory reset my phone, after first factory reset my phone is rebooting again and again(bootlooping)….
    What can I do to solve this?

    :First of all my WiFi and Bluetooth not working and it tries to turning on by itself…
    I need anyone’s help to solve all my problems

  3. When I do the manual update. The installation process restarts at 49 percentage.. Please help

  4. When I clicked ok on the 9th step,after 30% the phone went blank and got a pop up ” LGuserCSTool LG Mobile application has stopped working-Close Program” and the phone is refusing to start. Please advise.

  5. Hi, i have lg G3 D855 32gb international version and i have kitkat 4.4.2 and it’s rooted. I don’t understand how can i get Marshmallow update on my lg G3 please help me!

  6. thanks a lot guys its perfect working on my lg g3 D855 …good work and thanks again all of you …GOD BLESS YOU

  7. It doesn’t work for me. I have an LG G3 D855 running Lollipop 5.0
    Whenever I run the flash tool it keeps saying that I have to disconnect the cable and try over again. Any help? Thanks

  8. This is an official update, however if you are worry about manual update, it is advised to wait for the official OTA update.

  9. Hello! I’ve got a question about installing KDZ to my G3 (international 16GB). I’m afraid that if I flash my phone, I will miss some important bug fixes in software updates. Or google path updates. The question is, will I be able to install these updates after installing KDZ? Or can I install another KDZ with the updates then? Where can i find the KDZ if so?

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