My LG G2 was beyond gone! Can't believe your method worked! All these other XDA threads have outdated download links so thanks for keeping your links upto date!
After having tried to push Supersu to my phone via ADB, it soft bricked it so it doesn't get passed the logo. My computer would never recognize my device because it can't find the right drivers after installing every driver and MTP/Microsoft driver I can find online. It also never restarts when I hit the restart button.
I actually tried the stock recovery option which took MANY attempts to get to. After hitting the hard reset button, my phone just shuts off a second after the process begins!
This was literally the only option that worked for me. I was really close to just giving up on this phone but glad I kept searching. I did end up losing all my data and it even said failed when the process completed! It wouldn't restart and I had to do it manually when the flashtool attempted to reboot my phone at 80%. For anyone else with a bootup issue, this method is a nobrainer!