The non Atari carts, including Froggo's sent their code to Atari for a
validation key to be generated.
They didn't need it for the HES releases, though it may be in there anyway
(Export control laws on encryption tech).
-Matt Pritchard
Graphics Engine and Optimization Specialist
MS Age of Empires & Age of Empires ][
> -----Original Message-----
> From: Keith W Gerdes [SMTP:kwg@xxxxxxxxxxxxxxxxxx]
> Sent: Friday, November 13, 1998 2:41 PM
> To: stella@xxxxxxxxxxx
> Subject: [stella] 7800
>
> > How similar is this "backdoor" to the trick used
> > to make Lynx carts without Atari encryption?
>
> Maybe this was a bad choice of a word on my part (we
> don't want to start another 'encrypt' misconception),
> but it seems to fit IMO. :-)
>
> As pointed out, it isn't similar at all. Harry's card
> has a valid key - and he had the foresight for himself
> (and for others) to use a flexible design.
>
>
> To circumvent the key check without a boot ROM mod and/or
> to create a valid key is the real goal but there is that
> workaround in the meantime.
>
> One idea is to piggyback a valid 7800 cart. With extra
> circuitry, your cart would detect when to turn off the
> other cart. This was also mentioned for the Jag in rgvatari.
> 7800 cart
> connector
> your cart
> 7800
>
> Another idea is to look at non-Atari produced 7800 carts-
> Absolute, Activision and Froggo. There may be a solution
> there....dunno...
>
> ----
>
> > It still doesn't explain how Harry's cart passes
> > the valdation test in the first place.
>
> Harry sent the monitor to Atari and someone there ran
> the key program for him, so it has a valid key. He
> supplied full 2600 & 7800 docs and some 2600 games
> with the monitor package with Atari's permission.
>
> The trick is that he only specified the cart size as 4K.
> This allowed him to make patches in the other parts of
> the cart without bugging Atari for a new key.
>
> > I have looked over the bios and don't see anywhere
> > where you could steel control away from the bios
> > before the validation check happens, short of
> > putting some special circuitry on the cartridge.
>
> True. The question is how complex a 'hardware' solution
> will be and which method is best.
>
>
>
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