I think I figured out what I was doing wrong: either a) there was something lingering on my phone like a bootstrap remnant or something that was confusing the stock recovery or I'm an idiot and have bad eyes and kept clicking deny when superuser was asking permission for rom manager.
I ended up brute forcing .79 on as follows:
from stock recovery, install zip from sd.
Install fails,
reboot into bricked black screen
reboot into stock recovery again, keep pressing buttons and ignoring the recovery missing error.
Eventually recovery starts, flashed zip again.
Install fails quickly.
Reboot into stock recovery once more
Wipe everything, user data, cache, davlik, windows, plates.
Install
Have nerdgasm when it said installing LTE
reboot
.79 boots up.
I'm not sure if the permissions thing was the problem for sure since I only noticed it after I rooted .79 and almost hit deny on the left thinking it was allow. I'm too tired to try it now, but I'll try the install one more time another night.
Thank you kernelhappy. I was having the EXACT same problem as you and these instructions worked for me. Although it only took me two flashes to make it go through. (Didn't fail quickly the 2nd time, as it actually went all the way through) Thanks again!