[A83] Re: What is the problem with flash writes (in general)
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[A83] Re: What is the problem with flash writes (in general)
AFAIK, the reason the 89 (probably not even all HW versions)
can load a custom ROM, it that some trick was found (I believe it'd
something to do with the linking pins) with which the signature checking
was disabled, and the OS was just dumped into the calc w/o checking.
--(Peter-Martijn)
>
>
> If I had an 83+ I would 've tried it (and probably have come to the
> conclusion that it is impossible)
>
> btw: Isn't there on the 89 some program that patches the rom. Probably
> because they can enable flash writes, what we can't.
>
> ----- Original Message -----
> From: "Hyperbyte" <hyper@hysoft-automation.com>
> To: <assembly-83@lists.ticalc.org>
> Sent: Monday, July 09, 2001 10:46 PM
> Subject: [A83] Re: What is the problem with flash writes (in general)
>
>
> >
> > This would ONLY work if TI had been so foolish as to not include
> > the singing in Calc-To-Calc OS transfers.
> > I'm sure they weren't that foolish!
> >
> > You're welcome to try though, but I'm sure it won't work.
> > --(Peter-Martijn)
> >
> > >
> > >
> > > You don't need two calcs. You can also use a VTI to calc link and then
> use
> > > VTI's debugger to analyse things.
> > >
> > > The problem with simulating the computer though is that you first have
> to
> > > know what the computer does.
> > >
> > > ----- Original Message -----
> > > From: "Dan Englender" <dan@calc.org>
> > > To: <assembly-83@lists.ticalc.org>
> > > Sent: Monday, July 09, 2001 10:12 PM
> > > Subject: [A83] Re: What is the problem with flash writes (in general)
> > >
> > >
> > > >
> > > > I did something very similar to determine link commands for other
> things.
> > > I
> > > > used Calcsys's Link Console (actually, I wrote the link console for
> that
> > > > purpose). And, assuming you've got a fairly new version of Calcsys,
> you
> > > can
> > > > store the strings to reply with in RAM, and then send them by just
> typing
> > > > the address, instead of typing out the whole strings.
> > > >
> > > > If you have two TI-83P's (or know someone from whom you can borrow
> one)
> > > > you're in especially good luck You don't have to search through the
> ROM
> > > for
> > > > the proper reply (something I wouldn't really suggest doing), but
> instead
> > > > you can use one of the calculators to simulate the computer, and see
> what
> > > > the reply is firsthand.
> > > >
> > > > Or you could build a custom program, whichever you want :)
> > > >
> > > > -Dan Englender
> > > >
> > > > ----- Original Message -----
> > > > From: "Tijl Coosemans" <tijlc@hotmail.com>
> > > > To: <assembly-83@lists.ticalc.org>
> > > > Sent: Monday, July 09, 2001 4:09 PM
> > > > Subject: [A83] Re: What is the problem with flash writes (in general)
> > > >
> > > >
> > > > >
> > > > > You should write a receive program for your calc, which displays
> what
> > > byte
> > > > > you received from the graph link software. Then by examinig the
> TI-OS
> > > and
> > > > > see how that would respond you can make your receive program a bit
> > > > complexer
> > > > > as to receive and examine more bytes. And so you continue. And then
> > > > > (theoreticaly) you should be able to find what format your OS-file
> > > should
> > > > > have.
> > > > > ------------
> > > > > Hmm, this sounds a bit to easy maybe, but at least somebody could
> try it
> > > > > out.
> > > > >
> > > > > ----- Original Message -----
> > > > > From: "Tijl Coosemans" <tijlc@hotmail.com>
> > > > > To: <assembly-83@lists.ticalc.org>
> > > > > Sent: Monday, July 09, 2001 9:55 PM
> > > > > Subject: [A83] Re: What is the problem with flash writes (in
> general)
> > > > >
> > > > >
> > > > > >
> > > > > > > From: "Hyperbyte" <hyper@hysoft-automation.com>
> > > > > > >
> > > > > > > > > From: "Hyperbyte" <hyper@hysoft-automation.com>
> > > > > > > > >
> > > > > > > > > Simply put, no user-program can do it.
> > > > > > > > >
> > > > > > > > > Explanation:
> > > > > > > > > The flash chip has a "write enabled" line,
> > > > > > > > > only if this line has specific signal, one can write to the
> > > flash
> > > > > > > > >
> > > > > > > > > Now one could simply set this signal, if TI hadn't prevented
> > > that,
> > > > > > > > > they've somehow made it only possible for certain OS
> Rompages to
> > > > > > > > > set that value.
> > > > > > > > >
> > > > > > > > > (I think it's kinda obsolete now, since TI's released the
> app
> > > > > signing
> > > > > > key,
> > > > > > > > > but I doubt they'll insert _FlashWE and _FlashWD romcalls in
> new
> > > > > > OS'es)
> > > > > > > > >
> > > > > > > > > You could hardware hack that WE line, but then your program
> > > > wouldn't
> > > > > > be
> > > > > > > > distributable...
> > > > > > > >
> > > > > > > > Or, you can make your own OS, I mean TI-OS, which implements a
> > > > routine
> > > > > > that
> > > > > > > > enables writing to flash......
> > > > > > >
> > > > > > > How are you planning on signing that custom 'TI'-OS?
> > > > > > >
> > > > > > > AFAIK, OS'es need to be signed too, and I can't see how TI would
> be
> > > > > > > as stupid as to sign it's OS'es with the freeware private key.
> > > > > >
> > > > > > It's all theoreticaly of course, but when you attempt to send an
> OS to
> > > > > your
> > > > > > calc, your calc checks if it's a valid OS right? So can't you
> check
> > > that
> > > > > > code and see how that's done? It's also possible that the graph
> link
> > > > > > software checks a few things, but writing your own PC program that
> > > sends
> > > > > > data and doen't check anything shouldn't be that difficult.
> > > > > >
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