One of the should-be-zero bits that isn't has been proven to be making it actually CAS.w A1,A2,$0004(A4), but results seem to indicate both D1 and A1 and D2 and A2 go into the eventual result.
Doug has a more extensive writeup here:
https://www.downtowndougbrown.com/2...-mac-classic-ii-to-successfully-boot-up/And that writeup made Hacker News (
https://news.ycombinator.com/item?id=42824562 ), so we know that an '020 behaves the same as the '030 here (which isn't too surprising) and a 68060 behaves like MAME does. Also a lot of people didn't actually read Doug's post and went immediately to screeching that it's DRM or something, when it's very provably a bug.
