Actually, I have already done some research into that boot disc matter. I'm afraid there's no good news here.
As for the authentication of a CD, the boot disc is tied into that process from the very beginning. The executable contained in the boot disc will not work through your PAR without some serious manipulation, which is a task I haven't started yet (and probably won't start any time soon).
Disassembling the program might just aid in confusing you. After all, the code is designed to be used off of a disc, and not from the PAR interface. Cartridges have another "view" of how the boot process is organised, while a typical Saturn disc usually authenticates itself through the security ring somewhat early on. This also explains why the changes made by a "swap-aid" cartridge such as Magic Cart V2 or Super Strong Cart are in no way related to what the boot disc does (note: this is a guess).
I am right now too tired to explain this in any greater detail, so I'd just like to say whoever wants to go on turning the boot disc into a "boot cart" should go ahead! I'd really like to see this. However, you should prepare for a long ordeal, as this is going to take a while (unless I overlooked something in my research).
What I want to do is to break it down and see how it does it. This will help me on my research. I tryed to code my own but with no sucess,and also I need a host program for my hex editor(gameshark),and I think tis is the perfect thing to add it to.
well, this program HAS to do something with the CD interface, apart from authenticating itself... otherwise no cd's inserted after the boot cd will run, will they? However, there might be the remote chance the security ring is special and makes the Saturn 'forget' the CD protection for awhile...
damn I guess the aforementioned confusion is setting in already
Well, yes there are "hard calls" but I don't know how far they go, or what they are doing. There's a lot of confusing code, and I'm not really sure if you could discard the calls to the CD-ROM registers if you made a PAR version. The code actually expects to find a drive still at work with something I believe, since it checks for the status of a couple of registers (IIRC). Oh, and there's some work on command register, too. I can't find it all just now, maybe another day or if you remind me in PM.