Today, numerous official debug firmwares have surfaced for developers to take a peak at. Versions 3.50, 3.55, 3.56, and 3.60 were leaked by a developer who goes by the name of ConsoleDev. These firmwares are originally designed to run on official development hardware known as PS3 Test (Debugging) Units. The units are only given out to official Sony developers, but some of these consoles have found their way into hackers' hands over the past few years.
In addition to these firmwares being useful to owners of debugging consoles, they are also used in the development of Rebug custom firmware. The official debug firmwares are generally not useful to the average user. However, they are available for download below for anyone that wants to take a look at them.
3.60 – Download – D9D16378DD66AACCA6EF0FC8604F9F67
3.56 – Download – A42F46B276DAC43851250526A8A8CB7A
3.55 – Download – 3B6EBC594DE5586B5E289225F6D3164A
3.50 – Download – 0E4D8BDBBA47382C2BE4242F3327E1A1