Re: INPUT 64s from '85

From: Groepaz <groepaz_at_gmx.net>
Date: Thu, 22 May 2014 20:07:09 +0200
Message-Id: <201405222007.09982.groepaz@gmx.net>
On Thursday 22 May 2014, Spiro Trikaliotis wrote:
> Hello,
> 
> * On Thu, May 22, 2014 at 05:26:22PM +0200 Groepaz wrote:
> > all disks are protected, and you will need the g64 images to make them
> > work in modern emulators. there even exist a couple of cracks from a
> > couple different sceners (i am also interested in those, btw... :))
> 
> I only ever had the 8/87 issue of it. It was extremely easy to remove
> the protection: You had to change two (or was it three?) bytes on
> track 18, and the protection check was gone.
> 
> In fact, it was my first try in removing a copy protection, and it did
> not take too long.
> 
> I do not know about the other issues, but I do not expect it to be much
> more difficult there (at least, not for everything before 8/87).

yeah i know that "hack"... it doesnt work on all issues though, the protection 
changed (at least) 3 times. thats something i want to look at closer when i 
have proper dumps of all issues :)

derived from Issue 8/87 (second disk loader):
- Block 18/18 (offset 0x17700) Bytes $83 ff:
  $F8/$BB/$12 instead of $CF/$C2/$AE disables the copy protection.

(iirc correctly this is related to decoding of illegal gcr values)

-- 

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<George Jean Nathan>


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Received on 2014-05-22 19:00:03

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