Re: A little trick went horribly wrong (removing crackscreen)

[Chris <junk@trash.org>]

I attempted the same edit to the cracked Ms. Pac-Man many years ago.
There is a checksum performed on the title text which will cause a
crash if altered.

As I recall, there is a jmp (or jsr) at the start of the file to the
checksum routine at the end of the file.  Bypassing the checksum
routine simply involved NOP'ing (EA EA EA) the initial jump.  Then the
title text could be altered safely.

I still have the patch written down and archived away with my notes if
you're interested.  Although it shouldn't be too difficult to find it
with the info I just gave.


On Fri, 31 Dec 2004 03:19:50 GMT, Moll
<Mollyzkoubou@Spam.BettyKate.Spam.Spam.Spam.Dosius.Com> wrote:

>Laine Houghton wrote:
>> "Moll" <Mollyzkoubou@Spam.BettyKate.Spam.Spam.Spam.Dosius.Com> wrote in 
>> message news:Be_Ad.6028$PY6.4287@trndny02...
>> 
>>>Laine Houghton wrote:
>>>
>>>>"ATARISOFT PRESENTS"  is longer than  "DISKMAN PRESENTS"
>>>>
>>>>A binary edit would overwrite needed code most likely.
>>>>
>>>>Change DISKMAN to MOLLMAN and see if that works.
>>>
>>>Considering that there are spaces around the word, and the line length of 
>>>the bottom, I am still convinced that this is the proper text...
>>>
>>>Moll.
>> 
>> 
>> OK,
>> I'm not familiar with the specific product. I'd still bet you could take the 
>> origional and replace diskman with mollman and it would work. If not that is 
>> the the clue to the fix.. 
>
>I replaced "DISKMAN" with "EJTLNBO", and it crashed.
>
>I suspect there was a hacked checksumming code in there, or something 
>weird.  Being that it's data, it shouldn't be code... but you never know...
>
>Moll.