Ah that's ok then.. I guess the only other thing to do would be for someone to upgrade to OFW 6.20.. USB connect to their PSP and try to remove all software/hardware (whatever) files for 6.20 that we can have a peek at to see if we can make ourself a CFW from it..
Of course I know nothing about making a CFW and I expect its pretty complicated.. But it's always worth a try
Edit: What do programmers use to write and open these files so we can see the contents? That may be the key to editing them to prepare them for 5.50