Though that was very much a team effort, I knew nothing about USB before working on that. From memory, my contribution was mostly tweaking the code until it worked, I think my PS3 was the first to be exploited by PSGroove.

Though, I wasn't happy at merely copying the sequence of packets USB that lead to an exploit, so I spent some time trying to get a better understanding of how the exploit worked. That document is the result of my efforts.