whats the best twrp/custom install method on lg g3 d850

I have to reinstall the original firmware and reroot but I want a for sure way that I won't put that secure boot error back on or any other issue besides that to pop up. I tried the flashify method and ended up with that error. I'm not sure what I did wrong but. Help would be awesome. I used KingRoot to root

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I have to reinstall the original firmware and reroot but I want a for sure way that I won't put that secure boot error back on or any other issue besides that to pop up. I tried the flashify method and ended up with that error. I'm not sure what I did wrong but. Help would be awesome. I used KingRoot to root

from xda-developers http://ift.tt/25U8Sbk
via IFTTT