Samsung Galaxy Tab 4 (AT&T) bricked while trying to root While trying to root Samsung Galaxy Tab 4 (SM-T337A), it now says 


  System software not authorized by ATT has been found on your phone


Downloading the firmware through Odin didn't help.

Aside from taking it to the nearest AT&amp;T or Best Buy, is there a way to fix this by myself?
The best way is to download your original STOCK rom and flash it through odin. 

I need more info about your question. When you rooted it, did it sucessfully root? Do you know if the bootloader is unlocked? 

Also, what kind of recovery are you using?