Home Android How to Install Android 4.1.2 Jelly Bean Update on LG Optimus 4X...

The Android 4.1.2 Jelly Bean will be roll out for the LG Optimus 4X HD soon as a pre-released Android 4.1.2 Jelly Bean firmware for LG Optimus 4X HD is now available for download, the new update will bring many new apps.This guide shows you how to download and install Android 4.1.2 Jelly Bean update for LG Optimus 4X HD with leaked firmware.

DISCLAIMER: Please proceed the below guide at your own risk, Mobotalks will not be held responsible if your device lost data or gets damaged following this guide.



Download LG Optimus 4X HD Official Android 4.1.2 Update from here

Download KDZ updater

Download LG Optimus 4X HD USB Driver

Download this file is a compressed file that contains everything you need dowload

Before proceeding, BACKUP Phone data such as contacts, messages, photos, etc. because the internal storage gets wiped and you will loose all your data.

>> It is advisable to Reset the phone before upgrading which can result in better performance. To do so, open Settings > Privacy and select ‘Factory data reset’ option.

How to  update LG Optimus 4X HD firmware using KDZ updater

1. Install the LG Optimus 4X HD on your PC. Note: Do NOT connect the phone to PC while drivers are installing. Alternatively, you can install the drivers using LG Mobile update tool.

Important: If you’ve installed LG PC Suite before, then open the ‘Device Manager’ and Disable LGE Virtual Modem.


2. Extract the file KDZ_FW_UPD_EN.7z (firmware) to a folder on desktop. You can change the file extension from .7z to .rar to open it with WinRar.

3. Open the KDZ folder and run msxml.msi.


4. Enable ‘USB Debugging’ on Phone. To enable, go to Menu > Settings > Applications > Development and tick mark the USB debugging checkbox.

5. Then Connect your phone to PC with USB cable. (DON’T turn on USB storage)

6. Run KDZ_FW_UPD.exe from the folder you extracted before. (Run as Administrator)


Select the TYPE as 3GQCT and Phone Mode as DIAG. For ‘KDZ file’ entry, browse to the update file directory and select V20B_00.kdz.

7. Press the ‘Launch software update’ button. The flashing will start and you will see an ‘Emergency mode’ screen on your phone. Wait for 5-10 minutes until the process gets finished. Don’t touch your phone or disturb the KDZ updater at this moment.

When process gets completed, the phone will reboot automatically, then disconnect it from PC. (If phone doesn’t reboots itself then switch it ON manually only after noticing the ==FINISHED== confirmation in KDZ software update window on your PC).

Voila! Upon restarting, your phone should be running up Android 4.1.2 Jelly BeanOS. Visit ‘About Phone’ in Settings to confirm

If you run into any problems, feel free to drop us a comment below and we will reply you back ASAP with the fix or the solution to your problem.


17 replies to this post
  1. Is it possible to flash this fw onto a “Middle East’ purchased P880 ? Earlier when I had flashed the Euro_Open V10H ..everything except data was working. Will this happen again with this file n version of V20A?

  2. HELLO
    thanks for the article which i find very important for such a great phone
    and to get the leacked jelly bean instead of waiting for the official is what we, impatient owners, love.
    But (i know there is always a but:P) the steps u put doesnt work that way:
    if u do that the updater will not do anything
    but i was able to update the phone using the following missing steps:
    first u have to go to make the pc see the phone as modem and disable it and that is acheived by removing the battery–>connect the phone to pc zhile holding volume down—> when entered into S/W mode reinsert battery
    then you disable the modem from device manager
    also you have to put the update in emergency mode
    i found out that your data and apps will stay on the phone
    but if you want you can wipe the phone which might provide more phone stability
    i hope you do not think that i am making any disrespect to your article coz i am really glad that i was able to find this article
    and please update the article so that the users of the phone can enjoy jelly bean on their optimus 4x


  3. Thank you so much for you help AHMAD BAALBAKI. I did flashed the Jelly Bean on my P880 Today works great thanx again. Actually followed your guide and did it in 10 minutes.

    Have Fun..

  4. Its ok a made it. I have installed android 4.1.2 but the only problem i discovered so far is that it doesnt recognize sd card. Does anyone know how to fix this??

  5. No i didnt. Sd card got broken in flashing process, it doesnt work in any other phone so for you others that are planing to flash this rom TAKE OUT YOUR MICRO SD BEFORE YOU START.

  6. I tried this and other ways, but it seems my KDZ flasher begins, but just stops and gets stuck at one of the PARAM.

    Is there any way to fix this?

  7. make sure you have the same device p880
    and make sure to follow the steps carefully
    and it should be working fine
    the camera works fine(tested on over 10 devices)
    you can find more info on xdadevelopers where they acheived root unlock bootloader clockworkmod….
    good luck everyone

  8. thank you it is really good but the SmartShare app doesn’t work…there are some apps ,like these one, that when i open it wrote ” unfortunately, the app has stoppd”.
    what should i do?

  9. Hi i am from iran and have a question?!
    Can i use persian keyboard and persian language on my phone after updating this Rom؟!

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