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Assorted Cracks 1
Wings of Fury, VCR Companion, CrossWord Magic 4.0,
Tetris, RoboCop, Ikari Warriors
Plus
Dream Zone
Great Western Shootout
Task Force
Hard Ball
From: Michael Kelsey
Wings of Fury, VCR Companion, CrossWord Magic 4.0, Tetris, RoboCop, Ikari
Warriors, etc. etc. I have a solution. It took many days to come across this
one.
First, you need Copy II+ 6.5 or later, or the equivalent of a Bit Copier with
a Nibble Editor and then some patience. Also, it is much easier if you have a
Sector Editor with a string or hex search mode.
If you don't have a sector editor then skip this step. If you do, go to the
mode to patch the sector editor. Change all the YES's to NO's. Copy II+ will
overlook any checksum errors this way. Next, start from track $00, sector $00
and scan for these bytes:
AC 00 AC 00
In short this consists of periods and control-@'s. Write down the track of the
occurrence. If you get a "string not found" error than this method won't work.
Next, go into the Bit Copier and set it to edit mode. For those of you who
have Copy II+ press "/" when right before the copy process begins. Type in "0B"
and <RETURN> then "02" and <RETURN>. By the way, only copy that track where the
occurrence is found. Once the drive light stop spinning on the original drive
type "f" (I think that is the command) and enter:
E7E7E7
If you see this pattern repeated many times than you have found the copy-
protection. Starting from the first E7 (and including) count skip over six
of them and press "C" when on the seventh. Now type the following:
AF F3 FC EE E7 FC EE E7 FC EE EE FC <RETURN>
Press "Q" to quit the editor mode and continuing with Copy II+ like normal.
DO NOT COPY ONTO YOUR ORIGINAL!!!!! That is a very unwise thing to do
especially if the program doesn't use exactly this protection scheme.
Now, (if you like) got to you sector editor and read from that Track and Sector
that you wrote down earlier. If your Custom Patch settings have not been changed
then read that spot. No error should occur unless a disk drive copied poorly.
Now, go back to the PATCH screen and change it to DOS 3.3 PATCHED. Escape back
to the sector editor (the place with all the numbers and characters) and write
the sector to you BACKUP disk.
Reboot, you are done. This works with many Broderbund, Epyx, and other programs
where Roland Gustaffson implemented his floppy drive routine.
If you have questions, comments, send them to mkelsey@eecs.wsu.edu
Background behind the unprotection scheme:
------------------------------------------
After picking apart the protection scheme I found the bytes that were being used
to protect the disk:
EE E7 FC EE E7 FC EE EE FC
These bytes can be shifted around and even changed to suit the purpose of the
author. Thus, this protection scheme is flexible and changes from program to
program. The Hex bytes above have almost become a standard.
When sychronizing to the disk the floppy drive uses sync FF's. These bytes have
a binary construction of so:
1111111100 1111111100 1111111100
sync FF sync FF sync FF
The copy protection searches for the E7 bytes on the drive. Once it finds a few
it begins to read the copy protection. There is one limitation to the Disk II
Floppy drives. Zero bits (any more than two consecutively) are considered
invalid. Thus, raw bytes on the disk cannot start with zero bits. This
protection scheme is implemented because those zero bits, without special
hardware, cannot be read by conventional drives reliably. Specific programs
like Essential Data Duplicator 4.9 have the capability to control the write
process of the conventional floppy drive. This also works. But not everybody
has EDD 4.9, but most have Copy II+.
Any way, here is the raw bit structure of the Copy Protection
11100111 11100111 11100111 11100111 11100111 11100111
E7 E7 E7 E7 E7 E7
Well by adding those zero bits, the bits that the drive can't read once
sychronized, the manufacturer is able to "fool" the floppy drive.
By using the AF F3 FC combination the floppy drive is forced to sychronize onto
the normal disk data and then reads like normal DOS or ProDOS.
The Copy Protection scheme jumps midway into a bit stream to catch the necessary
data. Thus, by adding one or two zero bits to the E7 byte patterns you can
obtain the EE E7 FC EE E7 FC EE EE FC data pattern.
For example:
Data read by a conventinal copier including the zero bits.
/ E7 \**/ E7 \/ E7 \*/ E7 \**/ E7 \/ E7 \*/ E7 \*/ E7 \
11101110011100111001111110011101110011100111001111110011101110011101110011111100
\ EE / \ E7 / \ FC /\ EE / \ E7 / \ FC /\ EE / \ EE /\ FC /
AF F3 FC
10101111 11110011 11111100
\ FF / \ FF /
Seeing as I didn't mention this earlier, the copy protection scheme jumps in
midway into the seventh E7 byte. I placed 1010 to make the byte noticeable to
other people and to be a filler space. At the fifth bit the drive will read the
last four bits of the AF byte and the first four bits of the F3 and get an FF
byte. The next to zero bits in F3 act to sychronize the drive. Next, the drive
skips over the invalid zero bits and then takes the last two bits of the F3 byte
and then gets the first six bits of the FC byte. This, once again, fills the
eight bit data register and the last two zero bits force the drive to sychronize.
I tried many methods of implementing this program. The first four zero bits
1010 in the AF byte were needed simply because the IIgs and //c have a different
drive circuitry than an Apple IIe. With any more or any less bytes the copy
protection scheme on the original would just fail. So, if you come across
another method that generic copiers can duplicate (like this scheme) please let
me know.
Understand that the "/ nn \" for the top, and the "\ nn /" for the bottom
includes the bit that the slash is above or below, respectively. The top
demonstrates the original's data stream with the zero bits below the "*". The
bottom line illustrates how to obtain the special data from those extra undetect-
able zero bits. Hope this hasn't been too confusing. If you need help or would
like more information I can be E-mailed at:
Michael Kelsey
mkelsey@eecs.wsu.edu
Note: if enough people ask for me write a program do this automatically then I
will go ahead and write one up.
___________________________________________
From: jnichol@tso.cin.ix.net (Jim Nichol)
Dream Zone:
Change 22 DB C4 00 to AF DB C4 00 at all 4 of the following locations on Disk 1:
Block $1B7, Byte $A9
Block $1B7, Byte $DF
Block $1BC, Byte $F6
Block $1BC, Byte $12C
This supposedly is a HD compatible patch.