iPod firmware reverse engineered

There’s more than one way to extract a bootloader, and Nils Schneider has come up with a rather inspired one. He wanted to study the iPod firmware in order to write new software for the device, but couldn’t examine the code without first somehow extracting it. He ended up using a piezo element to output the firmware as a series of sounds, which he recorded and analyzed on his PC to convert the squeaks and squawks into a digital representation of the code. He essentially turned iPod and microphone into an acoustic modem, and wrote his own application to decode the signal. Then, he wrote it all up for posterity and posted it online in contribution to hacker lore. Hats off to you, Nils!

[Thanks Brian for the tip!]