Here comes an important add on… enables you to use old 1.50 kernel things on your latest M33 firmware.

Release notes:

150 kernel addon for 3.90 M33 (psp phat only)

– Copy 150k_addon to /PSP/GAME
– Get sony 1.50 update and copy it to the root with name “150.PBP”
– Run the program and done.

http://www.dark-alex.org/