Re: Crackers take note...

From: Nicolas Welte (
Date: 1999-07-30 17:24:43

Nicolas Welte wrote:
> The more primitive protections just checked if an error was present, the
> more sophisticated ones also read back the contents of the bad sector
> and made use of it. Of course there are much more advanced protections,
> but it looks like it is one of those, probably the second one.

No, it's the first one ;-) The software checks two times for a 22 read
error in block 18,18. One time at the beginning of the load and the
second time somewhere in the middle. Patching the checks is easy in an
emulator at runtime, but on the disk it is all encoded and I don't even
know where the second check is. Just found it by coincidence because I
had a breakpoint on the first check and the second one is at the same
address, but is obviously reloaded because my patch has been undone.
After patching that one as well loading went on until the menu appeared. 

So just creating a 22 read error on each copy seems to be the most
straightforward solution. I didn't manage to make it run so far under
any of the emulators PC64, CCS64 and VICE. Looks like they don't obey
error information in a D64 file. Is this possible? Maybe I'm gonna check
it on a real C64 with a real 1541 drive.

> BTW, who's the "Sister H" that is mentioned in 18,0? And what file
> starts at the mentioned block 26,2? It's not in the directory...

I now had a look at that secret file. Quite funny, but what does it

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