1. Extract the EBOOT.INI/BIN (located in GAME/SYSDIR) from the any ISO that you needed to run in this example its Motorstorm.iso
2. To extract it use UMDGEN, open the Motorstorm.iso from UMDGEN then extract the EBOOT.INI/BIN from there save it somewhere that you can actually find the file usaully on the DESKTOP
3. Then connect your psp to USB MODE then copy the EBOOT.INI/BIN file to the ROOT of your memory stick so its like (X:/EBOOT.INI/BIN) X means thats your memory stick well it just a sample
4. Then while your in USB mode copy the DECRYTER TO YOUR PSP LIKE NORMALLY (ITS LIKE INSTALLING ANY CUSTOM FIRMWARE)
5. After you have installed the decryter run the program and it WILL NOW DECRYPT THE EBOOT.INI/BIN FILE THAT YOU PUT ON THE ROOT OF YOUR MEMORY STICK
6. Then after its done go back to USB mode and delete the EBOOT.ini/BIN file from your root directory of your PSP.
& After you have done that locate the FOLDER NAME DECRYPTOR inside that folder there's the newly EBOOT.ini/BIN file that you needed and copy that EBOOT.ini/BIN file to your desktop
7. Then after that open up UMDgen again and open up Motorstorm.iso and DRAG THE EBOOT.INI FILE TO THE GAME AND THEN SAVE THE GAME AS .ISO
8. Then finally after you have save the game as ISO copy the new modified Motorstorm.iso to your psp then it should work %100.
Ive recently just had the same problem as i was using 4.01 m33-2 on a phat psp1000 the safe way is to go through the updates instead of straight to the newest. so you start with 5.00 m33-6, this takes you to the latest M33 update