i have no idea what the difference is between versions though!
what i can tell you is that my sds9 with os v6.0 behaves exactly as the manual describes.
even down to being constantly in omni mode and needing midi to be enabled each time in switch it on.
i did try some of the "reserved for future use" settings, but i didn't find any with an obvious effect
if there was an update with those two things fixed i'd be chasing it to the ends of the earth!
i played with midi mapping a fair bit, but i didn't get around to messing with sysex yet.
there are a lot of changes from the v4 rom though, i ran them through a hex editor with a diff function and only about 40% of the code is the same. but there might just be minor changes and the rest has just been shuffled arround. i don't know anything about 6809 assembly so i haven't even bothered trying to decompile it.
ewan.