Originally Posted by Peeodee
I had to install Chairfires SuperSU from the Playstore after you run the root process.
All is well now.
Sent from my SM-P600
I had to do exactly that to get root access. Flashing supersu.zip didn't help, but installing SuperSU from Google play after installing TWRP did the trick. All seems to be good (but of course I tripped Knox).