AT&T SGH-I337 UCUEMK2

Long story short, company is rolling out airwatch and I need to get rid of root. It's their phone, their policy. My issue is that all I have is a Mac. I've seen a few threads that link to the recovery firmware but it seems to be formatted only for Odin. Being on Mac, i'm limited to Heimdall which seems to use different files that I cannot find.

Can someone let me know where I can get the Heimdall firmware for my phone?

Thanks