byuu says:

fixed the pitch/speed of the VRC7, and added a 2280hz lowpass filter to match
hardware a bit more (it's kind of hacked in, but it works.) forgot to set the
echo buffer disable flag on the SNES DSP, which was breaking SNES games, so
that's fixed. started emulating the famicom disk system. so far just the icarus
BIOS + FDS disk imports (won't handle multi-disk merged ROMs yet), the basic PCB
mapping of PRG-ROM+RAM and CHR-RAM, some MMIO registers, FDS timer IRQs, and the
GUI connections to connect a disk (marked hot swappable.) I need more info on
the low-level details of how the ram adaper talks to the disk drive to proceed
further. But it's a start.