Unfortunately there isnt a windows based app which makes a MMS to take you straight too 5.50 GEN D3, however there is
You must login or register to view this content. This will load you too 5.00 m33-4 i think.
BTW THIS PROGRAM will delete the current data on the memory stick so make sure to back it up.
Instructions;
1, Load/Download 5.00 OFW eboot using the download button.
2, change the drive letter, to that of your psp, eg. g:/ , E:/ etc
3, Tick the format memory stick option
4, Create Pandora Stick and Voila!
Once done, pop memory stick in psp, then hold L trigger followed by putting the battery in, it will load from the stick as soon as you put the battery in. No need to turn it on.
If it doesn't bring up a menu, you didn't hold L trigger long enough
Then install 5.00 m33-4, welcome to CFW on one psp

Do the same for the rest.
Now when you get there tell me and ill explain how to get you on too the latest 5.50 Gen D3 - Prometheus unless you work it out for yourself.