[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)


The problem with using VTI is that it doesn't properly support the Flash
ROM, applications, archive, etc.  That means A) No Calcsys, and B) It may
get "
"confused" and break, especially as you're dealing with an OS upgrade.

And it's no problem to know what the computer does.  You just plug the
computer in the Link Console, do whatever on the computer, and look at what
bytes appear on the screen :)  You just have to send those to the other
calculator (preferably with a bulk send).  I haven't run into any really
long transmissions that would need it, but if it's necessary, I could add an
option to put log the received input as well as display it on the screen.

Of course, this method isn't useful for a final solution, but it is useful
for determining the nature of the communications.

-Dan Englender

----- Original Message -----
From: "Tijl Coosemans" <tijlc@hotmail.com>
To: <assembly-83@lists.ticalc.org>
Sent: Monday, July 09, 2001 4:37 PM
Subject: [A83] Re: What is the problem with flash writes (in general)


>
> 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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