Re: Cracking the 9010A ROM signature generator

Good luck, you'll need it! The code had to have been written
in some crappy compiler like PL/M or something. It's a
nightmare to try to unravel. To help you along, here;'s a
starting point: The calculated 'checksum' signature is stored
in location 0xF345 and 0xF346 once it has been calculated.
I got to the point where I had to reverse engineer the command
protocol between the mainframe and the pods, that's when
I finally had to give up.

Dave

----- Original Message -----
From: John Robertson <jrr@flippers.com>
To: <techtoolslist@flippers.com>
Sent: Wednesday, November 07, 2001 7:21 PM
Subject: Cracking the 9010A ROM signature generator

> I give up, I am way too frustrated by this stupid signature crap so I am
> going to dive into my 9010 and see if I can figure out how it is doing it.
> I first have to figure out if it is in the pod or the base unit, when the
> signature is being generated I see lots of activity on the pod data buss,
> so I am assuming the process is handled inside the stupid base. I am going
> to also see if I can figure out mathematically the difference between the
> fluke signature and the regular checksum by reading a small bit of data
and
> then doing a checksum on the same bit of data, then extrapolating it from
> there. I suspect that the unit is taking each data line and adding it up,
> then the next data line...and summing them all together or in series. Gah.
> digging into it tonight, perhaps I can report out later this evening what
I
> fine.
>
> Any suggestions? I am NOT an assembly language person...I can read it a
> bit, I understand the process, but I have not programmed with the stuff
> more than a few lines.
>
> If someone wants to disassemble the ROM in the base unit, the images are
on
> ftp://www.flippers.com/public and I found a nice Z80 disassemble called
> DZ80 http://www.inkland.demon.co.uk/dz80/index.htm heh, heh...
>
>
> John :-#)#
>
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>
Received on Wed Nov 07 18:53:07 2001