[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)




Root/Great Overall Dictator replies:
> 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.
> 

Ok, how is this  done? (the replaying of the strings?) It doesn't appear to
be in the docs. 

James L

> 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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