First, turn off your phone and press and hold the volume key to connect it to your computer. “Download mode” should appear on the phone screen. If the volume does not work, try the same procedure with the volume mute key.
1:Open the LG flash tool program and set it as in the following photo.
2: click on the folder icon next to the“Select kdz file” section and download it .find the kdz file and click the “Open” button. The LG flashtool program will be as in the photo below.
Now you have to choose “normal Flash” or “CSE flash”? The difference between “normal flash” and “CSE flash” is that it does not delete any data on your phone, it only upgrades the system, and "CSE flash" does a clean installation by deleting all the files on your phone. If you are going to drop your Android version, you should definitely do “CSE flash”, but if you are going to upgrade your Android version, you can use the “normal flash” option.
3:just click on the “Start” button on this screen.
4:finally, click “OK” button without making any changes to this screen.
After clicking on the “OK” button, the LG Mobile Support Tool application will open automatically on your computer and your installation will start from the LG Mobile Support Tool. When the LG Mobile Support Tool finishes loading, you can take your phone off the computer. * Use your new operating system goodbye .
Download LG Flash Tool 2014