[q] help with g3! topic

I rooted my g3 with stump root, I changed my mind and want to unroot it. So I tried to do so but I only have a Mac, I don't know if there is a way to unroot on Mac. All I want is to be able to upgrade to lollipop when I comes out, also, now when I put in my replacement battery, it says invalid battery and powers off, help.