'Software Toolworks protection--Black Hol'
Author:Lord Crass (guest: search)
Date: Sun, Mar 20th, 2011 @ 14:26 ( . )

Here's what it does:

After the title screen, it reads track 16 sector 20 (which seems to be mostly empty), after the read the drive head is at the tail gap (normally $55 bytes). It reads until it gets a $6A byte, puts it in the $309 location in drive memory. Then it reads the next 4 bytes and puts them reversed at $305-$308. Standard GCR decode follows and data is sent to the C64.

The C64 loads the data into $CB00, then EORs the 4 bytes it loaded together. Result must be $79 or reset occurs.

Force the value for a crack (I didn't check for checksums or anything like that) and the program continues and asks you to insert side 2, which I don't have. Or fix the GCR bytes in the image so they EOR (after GCR decode) to $79, which shouldn't be too hard.

BTW, the non-working bytes in the NIB dump you have are at offset $3DE97 and are:

6A 3D 5C D1 9F


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Replies:
--* Software Toolworks protection--Black Hol
3/20/2011 @ 16:44--J Achernar
3/20/2011 @ 17:28----Pete Rittwage
3/20/2011 @ 17:52------J Achernar
3/20/2011 @ 18:26--------J Achernar
3/20/2011 @ 18:37----------Pete Rittwage
3/20/2011 @ 18:41----------Pete Rittwage
3/20/2011 @ 22:23------------J Achernar
3/20/2011 @ 23:16--------------Lord Crass
3/21/2011 @ 08:23----------------Pete Rittwage
3/21/2011 @ 20:24------------------J Achernar
3/21/2011 @ 21:26--------------------Pete Rittwage
3/23/2011 @ 04:45----------------------hyper active
3/26/2011 @ 22:55------------------------J Achernar
3/27/2011 @ 13:45--------------------------Pete Rittwage
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