Re: Dungeon!
On 5 sep, 16:26, Bugman <btt071...@gmail.com> wrote:
> I collect and play any kind of old D&D based games. *I came across an
> interesting variant on Asimov called Dungeon! by TSR. It is a nibble
> image that works fine on emulators. *I much prefer to play these on
> the real machine. *However, it is always a challenge to get nibble
> images back to a real apple. *It still has copy protection that I
> cant
> get around. *It seems like a pretty common altered DOS type of
> protection. *I cant find any computist instructions for it. *I did
> find one that was an IOB for a couple of TSR games (including
> dungeons, not dungeon!).
>
> Does anyone have a deprotected version of this game, or know how to
> crack it?
It is a very interesting double on-disk protection :-)
The data marker changes depending on the track value OR-ed with the
ROM. Whenever you change track, $BE8B jumps to $BFC8 which calls $AE10
which calls $ADE0.
The second protection is based on nibble count of value $DD.
I suspect there is a third one based on the file name. I need to dig
that out.
By default, tracks 0 to 4 are copyable. Tracks 5 to $22 are protected.
With an rewrite of the on-disk protections, I have $12 good tracks out
of $22.
Let's go on...
antoine
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