From the iPhone Dev Team:
Disclaimer!! This is a purely technical post with no pragmatic use! There is no 3G unlock in this post. There is no iPod Touch 2G jailbreak in this post. It’s just a random technical post related to the 3G unlock.
We’ve been exploring different ideas with the 3G unlock, but this past weekend one of us hit a big snag. For whatever reason, all of our poking and prodding of the 3G baseband caused it to finally have a breakdown. After one specific exploit run, all of a sudden our baseband stopped responding to the OS. Even after multiple restore attempts, we were plagued with errors like this:
Somehow our software hacking had caused the baseband chip’s SPI bus to stop responding (so it looked like a hardware problem). Even though BBUpdaterExtreme reported the correct baseband version, it failed basic tests like memtest:
If you’re familiar with the baseband revision history for the 3G iPhone, you may have noticed that the above captures were done at the original 01.45 baseband. As dire (and hardware-related) as these messages sounded, though, there was a simple solution. We just updated to 01.46 and then downgraded again (because we can run unsigned code on the baseband CPU) to 01.45.
We tried to recreate the problem by using the same exploit over again, but it doesn’t appear to be reproducible (which is actually disappointing, as it might have been exploitable).
Anyway, there you go…a random, technical snapshot of dev team work.