Help Need help installing stock ROM

[Heat84]

I have an LG Tribute (LGLS675). I wanted to root my phone but I updated the firmware before I got around to(trying to) do it(I'm a newbie at this which is why I made that mistake). Whatever exploit the rooting apps use to do the rooting was apparently patched in the applied update(s) so I have to install the the stock ROM. LGUP doesn't see my phone (even with the uppercut mod). How do I get my phone to be seen as a COM port so LGUP can see it? I have the LG Drivers installed and USB debugging enabled.

I tried doing it in recovery mode but I got:
E footer is wrong, e signature verification failed

And why is there no subsection for my phone in the Devices section?

 

[Heat84]

I tried LGUP/Uppercut again and it failed, but 5 minutes later while scouring the internet for help, it saw my phone. I was able to successfully flash the stock ROM and root my phone.