Extending the ProDOS/SOS dual boot trick to DOS 3.3?

[lyricalnanoha@dosius.ath.cx (Steve Nickolas)]

When it comes to low level disk stuff, I fall flat.

One thing I'd like to be able to try to do is come up with a way to boot a
disk on both a ][ and a /// (][ loading the sector to $0800 and jumping to
$0801, /// loading and jumping to $A000, iirc?), such that the /// will load
my modified firmware (as Star Emulator does), then reset itself and do the
][ boot, causing DOS 3.3 to load, and boot as usual.

I believe it can be done, though I have no idea how to go about it.  Other
elements which are cosmetic in nature such as the SOS font load could be
done *after* DOS loads (if peek(-7)=51 - one of the signature bytes of my
modified ROM).

A possible use would be a disk similar to Apple Crunch providing games on
both ][ and /// without the need for a separate /// boot disk.

-uso.