-----------Labyrinth of Crete----------
A 4am crack                  2019-11-15
---------------------------------------

Name: Labyrinth of Crete
Genre: adventure
Year: 1981
Credits: Cliff Johnson, Allen Pinero
Publisher: Adventure International
Platform: Apple ][+ or later
Media: 5.25-inch disk
Sides: 1
OS: DOS 3.3

This disk was automatically cracked by
Passport. Here is the transcript:

                 --v--

Reading from S6,D1
T00,S00 Found DOS 3.3 bootloader
Using disk's own RWTS
Writing to RAM disk
T02,S02 Volume name is DISK VOLUME 254
Writing to S6,D2

The disk was copied successfully, but
Passport did not apply any patches.

Possible reasons:
- The source disk is not copy protected.
- The target disk works without patches.
- The disk uses an unknown protection,
  and Passport can not help any further.

                 --^--

Wait, what?

A quick inspection in my trusty sector
editor reveals how this disk was copy
protected. The disk uses a slightly
modified DOS 3.3 RWTS. Everything is in
the usual place, except for this code
on track 0, sector 3:

                 --v--

T00,S03
----------- DISASSEMBLY MODE ----------
; read data field epilogue nibble #1
002F:BD 8C C0       LDA   $C08C,X
0032:10 FB          BPL   $002F
0034:C9 DE          CMP   #$DE

; but ignore it
0036:EA             NOP
0037:EA             NOP
0038:EA             NOP

; read data field epilogue nibble #2
0039:BD 8C C0       LDA   $C08C,X
003C:10 FB          BPL   $0039

; also ignore it, and unconditionally
; branch to the success path
003E:C9 00          CMP   #$00
0040:D0 5C          BNE   $009E
0042:38             SEC
0043:60             RTS

                 --^--

The original disk's RWTS accepts any
epilogue nibbles after the data field,
including the standard ones that
Passport put in the deprotected copy.
Thus, no further patches are required.

Quod erat liberandum.

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A 4am crack                    No. 2114
------------------EOF------------------