Thank you for your advice!
GOOD NEWS!
I was able to get my Arduino firmware reprogrammed through DFU mode and the FLIP software!
Did I nearly use method 8 in this resource page to destroy my Arduino? 10 Ways to Destroy an Arduino — Rugged CircuitsRugged Industrial Arduino Microcontrollers
Also, I'm feeling a bit overwhelmed as to what I can do with the Arduino and motor controllers. Can I use my 1.2A/phase 4v unipolar stepper to its full capacity?
In the aformentioned link on method 10, am I understanding that I can't exceed 200mA of current on my controlled devices?
Some kind of link to an information dump to understand these circuits would be great also, if anyone knows of one!
Thanks again for your constructive input!