Lpc2000

Jaya,

http://www.arm.com/pdfs/DDI0234A_7TDMIS_R4.pdf
Chapter B3 about synchronized clock

Somebody at Philips went through some effort and wrote a very nize
summary on Dec 22

This should give you a good idea why the bootcode is not available in
source code:

----  quote  -------
2) I am going to replace the Philips bootloader. I have figured out
how to do it.

Replacing the Philips bootloader is not recommended. It hides the
underlying hardware and allows Philips to use new flash technologies
without impacting the end user. Philips Bootloader may reside in ROM
or write/erase protected flash making replacement impossible. In
LPC2101/2/3 the bootloader resides in on-chip ROM.

----  end quote  -------

Flash blocks change in size and timing. Providing a software interface
that you just need to call is much more user friendly than running
into support and debug issues every time an "expert" changes the code
to his/her liking generating undefined events in the flash programming
sequence or timing. 

It is fine that you disassembled the bootloader, nice exercise. Using
a reengineered version of the bootloader / programming software can
probably not increase the functionality but I can assure you it will
increase the trouble you get yourself and your customers in.

Overall, I do not understand you, if you think the CRP is not save,
then look at other devices and try to find one that is good enough for
your high standards. So far there have been 50++ messages but nobody
said that they were able to break the mechanism.

So, once you were able to set CRP in a device that actually can be
secured, which are all device but the LPC2104/5/6 and enable JTAG
without doing a chip erase I would be interested in your data. But
only then!

As a previous poster said, please feel free to set up a new Yahoo
group "Code read protection in ARM devices" and the enthusiasts will
follow you there.

As long as you post your assumptions, non-applicable bootloaders ....

Bob



--- In lpc2000@yahoogroups.com, "jayasooriah" <jayasooriah@y...> wrote:
>
> --- In lpc2000@yahoogroups.com, "unity0724" <unity0724@y...> wrote:
> > Reverse disassembly of bootloader is of no use in hacking the chip.
> > Regards
> 
> If this is true, Philips would have provided us with source for the
> boot loader.
> 
> You do not expect Philips to build defects into the boot loader.  It
> does not follow however that there are no defects, or that they cannot
> be exploited.
> 
> In a regime where obscurity is critical component of security,
> exposing internals is a high security risk.
> 
> Jaya
>