On my computer I had the patched ROM for the "Impossible" version of Super Mario Bros which worked fine on my NES emulator.
http://www.youtube.com/watch?v=3C1BSbq5aB0
When I put it in my Acecard 2 (running akaio 1.3b) and tried to run it on my NESDS emulator, it starts on some wierd water level...