Smile [Q] How to root Samsung Galaxy Note 3 with Sprint Stock firmware from samobile

Greetings-
I have tried to root my Galaxy Note 3 using the autoroot file provided by the great Chainfire ( much respect ). But it does not work. I just want to be clear, this is a phone, which I have reimaged with the Sprint stock firmware again, since I erased one file too many and could not boot it any more. Has anyone done this? btw, I got my image from SAMOBILE. Has anyone rooted a phone, ideally Galaxy Note 3, which they flashed with stock firmware after they rooted it once at least?
Regards