How to Update Korean LG Optimus Black KU5900 with Official V20L Firmware

Procedure to Update LG Optimus Black KU5900 with V20L Firmware:

  • After this, you need to extract the files of KDZ Software tool and from the extracted file click on the file called “msxml.msi” to open and this will install all the required tools.

KDZ_FW_UPD_EN Contents

  • After this you need to disable the LG Electronics Virtual modem which you can do from the path of “Control panel > System > Hardware > Device Manager > Modems > Right Click on the LG Electronics Virtual Modem” and select Disable as shown in the below screen capture.

Device Manager

  • Now, enter your phone in the Emergency Mode which can be entered by “pressing the Volume Up key + Pressing the Back Key and holding these both you need to turn ON the device”.
  • Now,  with the help of USB Cable you need to connect the same which you got at the time of purchase and then run the file named as “KDZ_FW_UPD.exe” and then select “3GQCT” and then after that “DIAG” in the “TYPE” section as shown in the below screen capture.


  • Select the “KDZ File” by clicking on the “folder” shaped symbol and then choose the file which you downloaded in the first step which is named as “KTF(KOREA).LGKU5900.V20L_00.kdz”.


  • Now, you need to ensure that the USB cable is not plugged out or interrupted or else there is a a probability that you may brick the phone. Also, after reboot, you may be asked to enter in the Language preferences as well as the Google account settings which are optional though as you can always enter these later.

LG optimus Black recovery

So, in this way you have successfully updated the device to the latest version of V20L in your LG Optimus Black phone. Do let us know in the comments section just in case if you face any issues as we will try our level best to sort out the same.

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