There are some games that will not work with your M33 driver. For example, Patapon will hang during loading the game. This can be resolved by choosing the Sony NP9660 Driver. But the M33 driver will work on most ISO games.
Follow the follow steps to change to the Sony NP9960 Driver>>>
- Press the Top Right button when you on the PSP
- Choose Configuration at the M33 Menu
- Go to UMD mode and select Sony Np9960
- Press the Back and Exit the M33 Menu