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The Bank Street Writer [1990] |
| User rating: | awaiting 8 votes (8 left) |
Credits :
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Production Info
Submitted by Radd Maxx on 27 August 2020
The first thing I noticed about this 1984 software was the reading of
errors off disk after all the seemingly pertinent files. In other words,
the original seemed to load files normally until the cpu asked for some
protection checking on the disk. As soon as the errors (that old early
1980's scheme) was read, memory was allotted for half a second and the
word processor fell into being.
After five years of 64 fever and two of cracking, I knew that I wasn't
up against much. Experience told me to make a fastcopy and try it out.
Everything then looked identical to the original except when the thing
asked for the errors on the original and didn't find them, it locked into
that familiar twilight zone. All this took 2 minutes to realize. I had one
place to go, and I've told you enthusiasts before, that all famous and
all-giving, the BOOT.
This boot is BASIC. Ha! Loads the screen, 6 or 7 files, then jumps to
our buddy, machine code at $1800.
1800 jsr $1a25
1803 jsr $5535
1806 jsr $18e5
1809 ldx #$ff
180b txs
180c jsr -----
180f jsr -----
Lots of subroutines. Believe me...lots of jsr's usually mean protection
or/and a program setup. So why would I lie? An author usually writes his
game and then use alot of jsr's to usually test what protection he wants
when he's finished. This is only logic, common sense and experience. That's
what made the 64, eh? Anyway, the next step here was to use this logic to
come to the conclusion of setting this:
210 sys 6144 ($1800)
to
210 sys 64738 ($fce2 - hardware reset)
We're now left with memory and a start at $1800.
Monitor please!
1800 jsr $1a25
1803 jsr $5535
1806 jsr $18e5
1809 txs (probably #$ff, I didn't check)
180b jsr $---
---- jsr ----
This is ALL logic. This is all LOGIC! After testing the sys 6144, I
found that this IS where the errors were read off disk. If we want to
break the protection, this is where we start...$1800. The ONLY logical
thing to do here was NOP out each jsr starting at $1800. The protection
is read here, and there are LOTS of jsr's. (Trust me!) So we NOP out $1800,
$1801 and $1802...we execute at $1800. No go. We load the boot in again and
sys 6144 ($1800), run it but having changed the next jsr (1803 jsr 5535) to
nop nop nop, we see that the thing takes off with no error reading. This
was it, right? One simple (not really) subroutine nopped into no-operation
bypassed the protection errors on the disk that couldn't be copied with a
nibbler or standard copier. The logic was good but the author was a rinky-
dink at the time.
This is it. Nop out that jsr and you have it. Very unexciting. I didn't
make any money cracking this disk but the protection author did! I think
it's prevailing capitalism.
- Manta |
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