I downloaded Armada from emuparadise and extracted the .cdi but both Demul and NullDC are trying to read it as an audio CD.
Selecting "Play Game" from the DC menu returns "Please insert game disc."
Both of these emulators are working with Sonic Adventure, but Armada isn't working.
Also, I downloaded the Armada .rar again - same exact file size and same error.