How to Dump an NES Game with no Mappers on CopyNES

So I have a game I desperately want to dump and preserve, but none of the mappers on the CopyNES work, despite it running just fine if I play it in the CopyNES. Anyone know how I can get this thing preserved alternatively? I would be much obliged.

Thanks!!

 

Turns out I need Mapper 156, which is used for Daou games. Anyone happen to have that file handy?

Thanks!