Here is the direct download link for VZW LG Software upgrade assistant Tool.
Once download, create folder for cab file and extract the BYREUTPUAC_22.214.171.124.cab to it
Inside the folder, you will find “BYRLauncher.exe” and “VZWNotiAgent.exe”
Run the ‘VZWNotiAgent.exe”,
Now you will find a vzw software Icon in the notification area (system tray).
Right Click that Icon, Click Launch Assistant
Now, Install the latest LG USB drivers for your LG G2
Set the USB connection mode to MTP
Connect your LG G2 to PC.
and start to upgrade your handset