How to: Flash big KDZ files – LG Optimus G, GK, G Pro, G2 and Others

For flashing low-end LG phones, you can use KDZ Updater for flashing KDZ files as described in our previous post here. But while trying to flash high-end quad-core LG phones with KDZ Updater, you will be stuck at “extract file error” while KDZ Updater tries to extract the necessary files. For flashing these > 1.2 GB KDZ files, you need to adapt a different approach as mentioned below:

When you need to follow this guide?

  • If you want to upgrade your phone to the latest version and are unable to do so via online upgrade.
  • If you tried rooting or some other stuff and got stuck in the middle.
  • If your phone is soft-bricked, it can only be revived by flashing the full stock firmware.

Guide

  • Download and install LG mobile drivers from here:
  • To make sure you don’t have any other instance of B2C installed already, go to Command Prompt and run this command:
    rd C:\ProgramData\LGMOBILEAX
  • Now download and install B2C app from here:
  • B2C installation might take some time. Successful installation will result in auto-run of the program. You need to close it before proceeding.
  • Download Flash Tool from here:
  • Connect your LG phone in S/W download mode to any USB 2.0 port on your PC and let Windows install the drivers.
  • Unzip the downloaded Flash Tool archive. Inside it, you will find “Windows Enabler” application. Right click at it and choose “Run as administrator”. You will see “Windows Enabler” icon in the notification bar. Left click at this icon once so that it turns to “ON”.
    windows-enabler
  • From inside the same archive, right click at “Up TestEX” application and choose “Run as administrator”. This might also take 10-15 minutes on first run. Be patient. After a while, “R&D Test Tool” will open.
  • Change ‘Type’ to “3GQCT” and ‘PhoneMode’ to “CS_Emergency”.
  • Select your desire KDZ file by clicking at the folder icon next to ‘Select kdz file’. Refer to screenshot below for reference.
  • Now click at ‘Normal web upgrade test’.
  • In the new window that opens up, choose ‘Upgrade Start’.
  • In the next window, just choose “OK”.
  • Now phone flashing/upgrade will start.
  • Don’t remove USB cable or batter from your phone during the flashing process. Your phone will restart at 90% but leave it connected until Flash Tools shows you 100% activity.
  • Congratulations, your phone was successfully unbricked/flashed/upgraded!
R&D-Tool
R&D-Tool-2
R&D-Tool-3
  • shrey

    stuck at 15%

    error-

    OnStepMsg STEP_TYPE_ENV_ERROR delete m_pLGCyonUpdate

    • arslan

      i have same issue … pls help

      • Gagan

        I also have same problem…please help..

        • Angel75

          same issue

    • Шохрух Шухратович

      Choose region Republic of Korea and language english. 100% works)

      • angel75

        doesn’t work

        • angel75

          i cannot choose language (blank list)

    • Saqib Naveed

      anyone fixed it ?
      I have the same issue

  • Γιώργος Κελάκης

    STUCK AT 47% PLZ REPLY

    • Try a different KDZ. It shouldn’t get stuck once started. The KDZ might be bad or your phone’s eMMC fault.

      • Areeb

        Hi. I have hard bricked my LG GX F310l. When I connect it through USB with my PC, I only see QHSUSB_DLOAD as a device. The only way I am able to access it is by QPST. But I don’t have and can’t find the right .HEX and .MBN files to run the eMMC programming. I don’t think I will be able to flash KDZ files either. Can you suggest a solution?

  • cuty

    driversmstrgen.sys file search fail.

  • Jades Ibusca

    can’t download philippines kdz

  • Cristhian Vasquez

    invalid sim card, sim not working
    how can I fix it?

  • Muddassir KhaAn

    DONE…!!
    ty v.v.v. Much… :**********

  • Jason Melling

    Hello- Thank you for the great tutorial but I am having a rather large problem, all is well until the flashing process is about 20% of the way done and it stops saying “Can not proceed due to low battery level, please charge your phone fully and try again”. The problem is my phone is fully charged, 100%. I been trying for 2 days now.
    Can anyone help ??
    Thank You, Jason

    • Athar Rajpoot

      man I got same problem

    • Athar Rajpoot

      problem solved

      • Arif Rezza

        Can you explain a bit, how your problem is solved

  • Travis Glascock

    hey guys. everything seems to be going well until the final step. the lg mobile support tool launches and says i have the most lastest software. I am trying to go from att to e980h telcel.

    • shahzain

      travis i have the same problem did u finid the solution

      • Travis Glascock

        My friend I haven’t found a solution! I hope too

      • Travis Glascock

        I haven’t found a solution. I did find a custom ROM and has allowed me to use my phone as I needed it too though

  • Athar Rajpoot

    Man After doing these.. LG support tool comes up says LG battery power is low
    I have connected my mobile to charger whole hour.. it charges or not … i get this error fastboot mode UDC_start();
    and nothing is happening
    but doing above instructed things
    everything is fine.. but LG support tool while installing stock rom gives battery low error

  • batjargal sanchir

    after i pressed on start upgrade it starts lg mobile support tool.HELP PLS

    • Shahzad Hassan

      Facing same problem. Start upgrade Button starts lg mobile support tool, Plz Help

      • Alpino

        Facing exactly the same situation. Whereas I have done flashing on my same laptop for many times one month before but now it starts Lg Mobile Support Tool. Also when I run UptestEx.exe, it opens up a small Log in window asking for user name and password etc.
        Has anybody faced this problem ? Hope Admin will reply quick.

  • Aljohn Tercenio

    Can you please help me? I just followed all the installation procedures but after i click the “UPGRADE START” in R&D Test Tool the mobile support tool will appear and start connecting and nothing will happen it should be the “Select Country and Language” window will appear right? But always the mobile support tool comes so anyone have the same problem like mine? i really want to back my original firmware but can’t flash it using this method :(

    • gag

      So version of current rom is lastest that cann’t UPgrade!

    • Adnan William

      i have the same issue any suggestions plz

  • kris

    How to root lg gk f220

  • Romulo Carlos Reis Alves

    Hi! I do everything correct. But, at step to run “uptestex”, the screen to load the KDZ don’t appears. Instead, a login screen appears, asking for “AD ID”, “AD PW” and “Employee Number”! How to solve this? I tried to flash with LG FlashTool 1.8, too… but it stops when I connect my phone, giving me an error. I’m triyng to update a branded D685 with V10A_02 to unbranded V10F_00.

  • vinskee

    after pressing Upgrade Start theres no popup about language insted the LG Mobile Support Tool loads and open and my firmware is 10b and it says iD83810b is the latest, im flashing D83810d help

    • Robert Gomez

      Use a small http server google it and you will find how to configure it. That problems happen because you get connected to the lg servers.

  • asad

    its 100% work but u msxml file corrupt and try it on window 7

  • Maycon Sanches

    Hi, my phone now is locked in SW/UPGRADE screen. The upgrade noto completed. I tried with Flastool LG, but not work. any sugestion?

  • Adnan yousaf

    How to put cell phone in S/W mode, i searched and tried many combinations but not succeeded?

  • Aamir

    should i disconnect the internet before start the process?

  • Aamir

    after i pressed on start upgrade it starts lg mobile support tool. No further process started

  • Aamir

    after pressing Upgrade Start theres no popup about language insted the LG Mobile Support Tool loads and open

  • Aamir

    Can you please help me? I just followed all the installation procedures but after i click the “UPGRADE START” in R&D Test Tool the mobile support tool will appear and start connecting and nothing will happen it should be the “Select Country and Language” window will appear right? But always the mobile support tool comes so anyone have the same problem like mine? i really want to back my original firmware but can’t flash it using this method

    • sajid

      Same problem here

    • Sajid Khan

      Got the cure!…
      Install latest flash tool 2014
      and follow the same steps!…. as mentioned above!…

    • Djaber

      me too have this problem :/ i have g3 rom but i want to flash official kitkat 4.4.2 any help ? …

      • Robert Gomez

        Use a small http server, google it and you will know how to configure it. Shttp

  • Mazzahir Abbas

    All users facing problem should Avoid this method…….. Me too followed the steps above and get me phone Bricked. Always Download Mode screen. So here is what is did that solved my problem and I am using my phone without any problem. Here what I did… My Phone Model is F240L….
    1- Ditch your Laptop if you are using one. Use your PC which has a Fresh Windows 7… Yes Windows 7
    2- Install LG United Drivers for your Phone. I used the above one in the this post.
    3- Now Download LgFlashTool 2014 and .Kdz file for your phone model. Use XDA for that.
    4- Now put the downloaded KDZ file into the folder of LgFlashtool.
    5- Put your phone in Download mode by Pressing Volume Up and Volume Down together and then insert Data Cable into the phone. (Always use USB ports which are on the back of PC. No extension Usb cables No Front panel Usb and must use Usb 2.0, usually black one. Usb 3.0 are Blue in most of cases)
    6- Let the Windows install the Drivers ( You will see a window popup showing Three Drivers being installed). When all drivers installed. Open LgFlashTool folder.
    7- Now Right Click onto LgFlashTool and open it with Administrative Rights.
    8- Onto the main screen. You see two Boxes with Options. On the left Select CDMA, on the right Select CS-Emergency. Now browse KDZ file and select it from the LgFlashTool folder.
    9- Now Click CES Update…… Now a window pops up and just click on Update Start. Wait some seconds and another window pops up with Korean Language and Country. Now Just click OK.
    10- Sit back and be patient. A window pops up LG Update and it checks out your USB Connection first. If it fails DONT PANIC. Remove USB cable, Remove your Battery and Close the FlashTool program. Again Put your Phone into Download Mode and Launch FlashTool with Administrative right. Again select the options as previous.
    11- This time USB checkup Should complete. and then Update will start. Relax now phone will restart at 90-95% and then let the phone come to Setup screen. Remove USB and that’s it.
    Please use Quality USB Cable. I used cheap cable and get USB connection error twice, then I used Samsung Usb Cable and it went perfect.

    • Andrey Fernando Flores Balderr

      where can I find the KDZ andthe other program??

    • Quiescent Heart

      thanks dude :* … cheers

  • Antonio Caser

    These your files are full of virus. – NOT DECLINE – WILL SPOIL YOUR PHONE.

    Esses seus arquivos estão cheios de vírus. NÃO BAIXEM – VAI ESTRAGAR SEU APARELHO.

    LIXO – LIXO – LIXO – LIXO – LIXO – LIXO – LIXO – LIXO – LIXO – LIXO – LIXO – LIXO – LIXO – LIXO

    TRASH – TRASH – TRASH – TRASH TRASH – TRASH – TRASH – TRASH – TRASH – TRASH – TRASH

  • happy

    Excellent 100% Success
    I have the LG D838 32 gb model
    thanks… worked like a dream … followed your instructions exactly…
    (reboots around 82% for me)
    flashed firmware D83810f_00.kdz using windows 7 SP1

    (why did I flash the KDZ file because I had installed Lollipop 5.01 OTA and loved it.. but couldn’t accept the incredibly slow charging times)…. can not believe Google released it with that flaw
    Once again thank you for your information…..

  • Athar Rajpoot

    for those who get battery error
    just half second before it is going to check battery ” remove and plug back in the cable after battery check passes it will take second or two ”
    and for those who get error cannot copy or shows some error DONT PRESS ANYBUTTON JUST MOVE THAT ERROR WINDOW TO SIDE TO SEE PROGRESS DONT CLICK ANY BUTTON

  • Niner Patatuchi

    I know this post its kinda old but I want to know what do I have to do if the pc doesnt recognize my device

  • carlos

    Please I need fix my cellphone LG C800, and I need the KDZ. Somebody can send me to my email? Please carlosdmm@nauta.cu

  • Bhoboghure Omi

    After selecting country (Korea) i cant find any language in Language field.

  • Shahbaz Haider

    I have lg f200s few months ago i flash it with kikat 4.4.2 firmware now i want to restore to offical firmware i downloaded it but flash tool is giving me error alot of question marks with s/w upgrade written between them any help please?