[A83] Re: What is the problem with flash writes (in

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: What is the problem with flash writes (in
From: Hyperbyte <hyper@hysoft-automation.com>
Date: Tue, 10 Jul 2001 15:51:35 +0200 (CEST)
In-Reply-To: <3.0.5.32.20010710090756.0084e220@pop.snet.net> from "Gavin Olson" at Jul 10, 2001 09:07:56 AM
Reply-To: assembly-83@lists.ticalc.org


This check is done in the boot code of the calculator.
This boot code is loaded from real Read ONLY Memory.
You could ofcourse remove the bootcode chip, and replace it, but 
I think that would be rather dangerous.

Slightly better would be to hardwire the write enabled line to a 
write-enabled state, and then simply write the OS to it.
(Would be nice to implement certain relly useful non-native math 
functions into your TI83+ without teachers noticing it at all.)

--(Peter-Martijn)

> 
> >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)
> 
> 
>

Follow-Ups:

[A83] Re: What is the problem with flash writes (in

From: "Kirk Meyer" <kirk.meyer@colorado.edu>

References:

[A83] Re: What is the problem with flash writes (in general)

From: Gavin Olson <gtolson@snet.net>