With the new updates with the Ouya it is unable to natively load Fat formatted devices. Attached is a PDF that explains a work around you can use. I also attached how to map controllers on the Retrode to the Ouya.
Hopefully this helps people that use the Ouya.
How to use the Retrode on the Ouya (http://korori-gaming.com/uploader/view/BFFD534DB0D68FF)
How to use the Retrode Controller on the Ouya (http://korori-gaming.com/uploader/view/398EA44481446E0)
You might have to play with the n64 one a bit more but the basic stuff is that tutorial.
Korori