I have the Samsung Galaxy S4 SGH-I337 Model with AT&T. I've tried some tutorials online and some tutorial threads that I found on here. The problem is Odin it says fail each time I try to flash the AT&T 16 pit file with the MK2 file. I'm putting the MK2 file in the PDA. It's also soft bricking my device each time. When I boot up my device it automatically goes to Odin mode with the smart phone icon with a triangle and the computer icon. Under that it says "Firmware upgrade encountered an issue. Please select recovery mode in Kies & try again." To fix this issue I have to use the pit file only in Odin. Everything else fails. The reason I want to downgrade is so I can root my device so I can tether my phone data to my galaxy tab. None of the non-root tether apps works for me in the play store. Any help?