Working with the original:
1) Make sure to place write protect tabs on the original to
protect it during the breaking process.
2) Turn the computer off and insert your reset assembly into
the cartridge port. Turn the computer on again and from your
utility disk, load the $C000 monitor <> LOAD"49152",8,1 <>. Sys the
monitor in with SYS 49152. Remove the utility disk from the
drive and replace it with your original (Side A). Load the file
ICONS <> L "ICONS",08 <>. The disk log tells us this file
resides at $6000 in memory, so let's start our disassembly at
$6000 (D 6000). Cursor down through memory and notice the
decryption scheme at $6005-$6012. Remember from the
introduction, this is the heart of this protection scheme.
3) Let's execute the code at the beginning of the decryption
scheme. Start it working with G 6005. The drive should start up,
and in a short time, stall again. Reset the computer and re-SYS
the monitor back in with SYS 49152. Disassemble memory at $6000
again. Cursor down through memory and notice the code HAS
changed. We now have all the data necessary in memory to break
this program. Let's save our altered ICONS file back to the
backup.
Working with your backup:
4) Checking the disk log shows that the ICONS file starts at
$6000 and ends at $69AD in memory. With the backup in the drive,
save the ICONS file, remembering to add one byte to the end address
<> S "@0:ICONS",08,6000,69AE <>. Now turn the disk over and save
the file to Side B as well.
You may now load and check your backup. You'll find it to be
completely broken, and now it can even be fast copied. For those
who want to see the actual protection check, you can go back
through the same steps as before. When you do the G 6005, just
reset out after about ONE second. If the drive is allowed to run,
it will pick up the break data from the original, and hide the
protection check in memory.
BANK STREET SPELLER : BRODERBUND
Procedure:
Loading the original produces a rattle free load, and an error scan
shows no standard errors. A backup made with the C-64 Fast
K.J. REVEALED TRILOGY PAGE [56] (C)1990 K.J.P.B.
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