I was able to root my phone properly. The key reason to root the phone was no access to tethering. Details for my situation:
Samsung S4, i337, MK2, andriod 4.3 from AT&T. I unlocked it and have been using with Rogers here in Canada but the tethering gives the Mobile data not available/invalid sim error.
I researched for solutions here and on google and all solutions required root, so I rooted the phone using the guide mentioned above. After that I used the method in this link
However, since I am using non-AT&T sim, this does not work any more. Further I uninstalled all AT&T apps using ES file explorer but still no luck.
Then I figured out and tried other solutions like FoxFi, etc etc.
Then I used the framework file from the thread below which was able to turn the toggle on.
Now I can see the the tethering tuned on. I can also connect to the wifi. however, it does not connect to internet. I think I am still missing some piece. I cannot post in the thread above as it is developers section. But I am lost, there is no further solution that I could find on forum or google. My mobile data works fine, I can turn on the tehter, I can connect to the hotspot, but I cannot connect to internet. It is a phone issue for sure.
I am not sure what to do in this case. Any help will be greatly appreciated.
Edit: I have tried this as well, but it did not work.