Downloads (all files)
Download all the files and extract zips.
Install drivers and LGFlashTool (Flashtool will install to path C:\LG\LGFlashTool)
Add the unzipped tot (firmware) and Megalock dll file to the LGFlashTool folder.
Put phone in download mode: Turn phone off, push and hold volume up and plug USB cable into phone
Open device manager (Windows Start>control panel>device manager)
Select Port connection for phone (COM and LPT>LGE Android Net for VZW USB Serial Port)
Change the port to COM41 (Right click on the specified port, select properties, left click port setting tab. Click advanced. Change COM Port Number to COM41. Click OK. Click OK.
If you don't see the phone, click View in Device Manager, then click Show Hidden.
Start LGFlashtool. Specify the dll and tot to flash by checking "Select manual mode." Left click the "..." button and select the dll. Left click the "Add" button and select the tot. Click OK to close the file selection window.
Click the yellow arrow and wait patiently. Loading the firmware takes a few.
When FlashTool shows Ready, disconnect the phone for ~5 secs. Upon reconnecting the phone, FlashTool will automatically run. This will take a few moments, so go get a cup of coffee. When the phone shows a blue screen with a bid red 3, you're good to go. Disconnect the phone and pull the battery briefly. Restart the phone and redo the setup. Shutdown Flashtool to prevent any accidents when rerooting.
New LG G3 for you and me! [emoji106][emoji106][emoji106]
Here is an alternate method using KDZ developed for people who took the C update.