Updating psp firmware 4 21 to m33
Using this trick, and with a bit of guesswork, hackers spotted that navigating to addresses such as file:///disc0:/ would allow files from the UMD to be viewed.Further exploration of a UMD disc using this method led to the discovery of the format of the executables that the PSP uses.A hacker by the name of Dark Alex had released a custom firmware called "Dark Alex's Open Edition firmware" which opens the firmware but allows users to use the existing feature set of the current edition.
The installation is complex, requiring a Pandora Battery and Pandora memory stick, a non-Slim PSP with firmware 1.50 or custom firmware that supports 1.50 kernel, and of course, a PSP-2000.
As always, this is not for the faint of heart nor anyone who hates carefully reading and following instructions, as there is always a possibility of bricking your brand new PSP-2000. Full instructions for the installation can be found here.
This reportedly caused more buzz in the community than any recent official offerings for the device.
One of the drawbacks of downgrading the PSP is that new legitimate media may require the presence of a new firmware edition.
EDIT- Go here scroll down to the bottom of the post and click the second link for hellcat's RF.