I know this thread is old, but I want to clarify some of the firmware types.
Internal/Development Tool - firmware with little security, allows plain stuff, what game dev's use.
Testing Tool - (like the thread one) firmware like retail, but a few drivers to communicate with the devkit (sm1 for example), along with bsod and debug utilities, what debuggers use.
Retail - the locked up firmware's that Sony distributes, what consumers get.
And example of say an internal firmware would be the bogus, witch allows plain modules. The 6.00 TT would be a testing tool that allows for crash tracing and such. The retails should be obvious.