Mayflash Gamecube Adapter and SHIELD TV Pro Struggles

Hello!

This is my first topic so I apologize for any error regarding standard procedure. I have been having a very hard time using the Mayflash Gamecube Controller Adapter with my NVIDIA SHIELD TV Pro in Retroarch. I have tried reading some forums and testing some things out, but no luck. Often I can get the buttons working, but the D-Pad, Control Stick, and C-Stick do not work.

Any help would be appreciated. I love Retroarch and I would really love to be able to use my Gamecube Controller. For the record, I tested it out on my old PC and the controllers worked fine.

Thanks!