From [The Hidden Boot Code of the Xbox – Xbox-Linux][XBox Hidden Boot Code]:
> 512 bytes is a very small amount of code (it fits on a single sheet of paper!), compared to the megabytes of code contained in software like Windows, Internet Explorer or Internet Information Server. Three bugs within these 512 bytes compromised the security completely – a bunch of hackers found them within days after first looking at the code. Why hasn’t Microsoft Corp. been able to do the same? Why?
Pretty good article, BTW. Must read for firmware/hardware hackers.
[XBox Hidden Boot Code]: http://www.xbox-linux.org/wiki/The_Hidden_Boot_Code_of_the_Xbox