[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)
> 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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