FAMICOM SOUND DEBUGER
At some point in development, there was a "FAMICOM SOUND DEBUGER" mode, similar to the one from Magic Darts. In the final release most of the functions used by this debugger were moved and as a result the code itself is broken.
Silva Saga Sound Test Ver1.0 Music 00 Effect 00 Pause Cont Fade Out
There was one more sound test mode at the development stage, but unfortunately it was broken by the latest modifications. The whole of bank 17 was intended for sound debugging code, another bank with system routines should be mapped at 0xC000. But either there is no code anymore for these routines or they were moved.