I dumped a ROM! (and I like it)
Currently, dumped KORG X2 ROM.

 Luckily, "The V55PI instruction set is upward compatible with the V20/V30 (native mode) and V25/V35 instruction sets"

And V20/30 is just 80186 clone, so "It's easy to find suitable disasm", I thought.
Bogus! ( I was hoping for IDA has 80186 support, but...
But I found old good dosbox-running app, called Sourcer.  Checking it out now.

P.S. Feel free to contact me, if you need Korg X2 fw file. i'll dump X3 fw soon, and some morre ;)