Keep holding Volume Up until you see a screen with a small image or text saying “Download Mode” (or a firmware update screen).
To get from EDL to standard Download Mode or to use it: How to Open Download Mode on LG V40 ThinQ
You should now see a screen that says “Firmware Update” with a progress bar at 0%. Keep holding Volume Up until you see a
: If your phone is stuck on the LG logo and won't turn off, hold Volume Down + Power until the screen goes black, then immediately switch to holding Volume Up while the USB cable is connected. If your hardware buttons are broken or unresponsive,
If your hardware buttons are broken or unresponsive, or if you simply prefer a software-based approach, you can use the Android Debug Bridge (ADB). This method requires that is already enabled in the Developer Options of your phone.