Default Phoe rebooting after root

Hey guys, first of all, sorry if this is in the wrong place. I tried posting in the thread of the tutorial I followed but it said I should see the Q&A subforum.
I tried following this tutorial with my brand new s4 mini, my phone started rebooting out of nowhere. The same thing happened with my x peria arc, my last phone. I'm afraid this will keep happening to this new phone and I'd just like to know if there's a solution. Thanks in advance!