Dark_AleX / Team M33 has released the much anticipated new custom PSP firmware 5.00 M33-4. which will allow you to run both new PSP games requiring this firmware, and homebrew/emulators to run on your PSP as well. Dark_Alex’s PSP Firmware 5.00 m33-4 has these changes:

- Speed selected for umd/iso was not properly locked in some new games that used scePower_EBD177D6 instead of scePowerSetClockFrequency to change speed.
- UMD/ISO speed settings now apply to PSN games too.
- Fixed libupdown.prx connecting to dark-alex.org instead of sony when npsignin_plugin checks for a new version and m33 update is enabled.
- Iso file descriptor was not closed in driver deletion
- Added a shutdown command to vshmenu.