Making Neo Brickproof, was comments after reading Wiki

[Werner Almesberger]

Simon Matthews wrote:
> If you do find a chip with a small protected page i might be interested
> in writing the loader i have outlined.

Thanks !

> As long as the bootstrap code  reprogramming is bullet proof or you
> don't see the need for changing the boot code i can't see any problems
> with one large bootstrap.

Yes, that emergency bootstrap should be both bulletproof and immutable
(with very few exceptions), but you have basically the same code also
in the part of the system that is meant to be easily upgradeable, so
even development that's very close to the hardware doesn't need to
touch the recovery stuff.

Perhaps a good analogy would be the recovery CD one may have for a PC.
(Only that PC hardware can change a lot more than what's in a given
phone. About the worst that could happen is that it may not recognize
your brand-new 1TB uSD card, so you'd have to find one of the old
and boring 4GB ones, or use USB :-)

> I looked at using USB a few years ago and decided it was too convoluted
> and complex. IMHO a powered Ethernet variant would have been a much
> better arrangement that the USB mess.

Yeah, USB is a fine triumph of NIH. And of course, they had to add
isochronous transmissions. That's to low-level communications about
what the video phone is to telephony :-(

- Werner

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 / Werner Almesberger, Buenos Aires, Argentina     werner at almesberger.net /
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