Re: Memcals

["Dave Zug" <dzug@delanet.com>]

As a person interested in crypto techniques my guess on the scrambling was
that they simply swapped a few address lines and a few data lines. If you
look at them side by side your peripheral vision picks up every other pair
of bytes matches factory, and the rest is off by what appears (in 30 seconds
worth of looking I did) to be some pattern of bit swaps in the differences.
pretty cool. this protection wont safeguard against duplication though, if
indeed thats what is done.

If this is true then if someone read it from the pins that plug into the
header rather than the chip legs it may look right. Just a guess dont waste
time on it if it doesnt make sense.... I only ever read 4 chips and all were
cars of mine. One was aftermarket and came out scrambled this way and I
didnt keep the file (it was made in 88 for an 89 car! geeze cutting edge!)..
I lost the Quad-4 chip I read, I gave it to one person on this list years
ago... (still got it maaan?)

of coarse the other possibility is the reader that was used had a couple of
unconnected wires  duuuh ;-}


----- Original Message -----
From: Bruce Plecan <nacelp@bright.net>
To: <gmecm@efi332.eng.ohio-state.edu>
Sent: Saturday, January 15, 2000 11:39 AM
Subject: Re: Memcals


> I "heard" that they are doing that now <g>.
> Grumpy
>
> | I haven't actually tried to program anything with it yet (just got my
> | EMP-10), but seems to work fine. I've only got two memcals - a V6
cavalier
> | (ARYF) and a '89 Hypertech TPI 350 A4 Camaro (which seems to be
> scrambled).
> | Andrew
>
>
>