Exclamation [Q] Need some help. Please!!!

Hey guys, need some help. I flashed the hyperdrive rom on my att galaxy s4. Couldn't get data to work on it so I decided to flash dark carnage instead. Followed all the steps from safestrap, when I go to reboot my phone it stays stuck on the samsung custom boot screen. Been looking around like crazy trying to find out how to use Odin to go back to original mk2 firmware. Please can some one help me out on how to do this