LG phones firmware come in kdz format sometimes TOT but you can flash it with the flash tool.
for windows pc
Below is a guide on how to flash LG phones firmware for the purpose of downgrading, reviving or upgrading your phone in kdz format.
First download flashtool here
Extract the download file and double-click/Run LGFlashTool2014.exe file to Open LG Flash Tool.
If it doesnt run then you will have to install and run visual C++ runtime library http://adf.ly/1a6VTv
Download and setup lg phone driver here
how to boot into download mode in LG phone
ONce flashtool is installed open it will look like the picture below
Now load your firmware in kdz format
NORMAL MODE: flashes without wiping data but only do this when you need to fix system error or something to avoid getting error when flashing a firmware other than the one already in the phone.
CSE MODE: fresh install wipes it clean back to factory rom.
Now click on start
No need to select language it will change to english by default but you can cure your curiosity and choose
Now wait untill 100% and enjoy..