[Q] KNOX Bricked Samsung Galaxy S4 Bricked + Odin won't work

So I forgot to freeze/remove KNOX from my S4 when I flash CWM recovery. I ended up with the "System software not authorized by AT&T has been found on your phone" message. I tried to download the firmware from Samsung and flash it with Odin, but Odin failed to work. Right now my phone is a useless brick and nothing I can find has any effect. Is there a way to remove KNOX or change my recovery back to stock? How do I make Odin work properly?