This is supposed to be a unrooting script that works on any phone. My f3 is my only phone right now so can;t try it myself. Maybe if this works unrooting before any updates may help prevent soft bricking you phone.

Find it here
How to Root & Unroot Any Android Device: Simple StepsTechDistinct

Never mind sorry waited post. Didn't read it properly. Guess you would have had to use his root script first in order to unroot with his script. Makes sense. But if your not rooted yet maybe this is a way to do it allowing for unrooting if needed.

 

I have the superuser app that came with mottochopper root method not supersu. Also do not have busybox installed.

 

I read something somewhere that after you unroot a lg phone there is a file somewhere that lets VM or other carrier know that the phone had been rooted at some time. LG Efuse or something like that?