[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, 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.
> Is this check for signedness a hardware thing or a software thing? Could
an
> approach like the HW2Patch for the TI-89 be used to override any check for
> a signed application? If it is software, I don't see how a new OS could
be
> prevented from being put on the calc if you used a custom link program and
> did a total wipe of the flash chip ahead of time (hold a hot line to the
> pin on the chip, if necessary)
The problem with using a custom link program is that that program needs to
be able to enable flash writes, which is impossible since you can enable
flash writes only from a few rom pages (as Dan pointed out). That it can be
done with a hardware hack is probably true but it would be much better if we
found a software hack.
I think we should start with examining how the link communication works and
how the calc checks the signature. That would bring us a whole lot furter.
Tijl Coosemans
References: