MPH may be a bad ass coder but his "Engrish" sucks.
This is my interpretation of his Game Loader instructions. I still haven't been able to get it to work, so let me know if I misinterpreted any of his instructions. (I got it working!) Hopefully this will help some newbies out.
Here goes nothing...

MPH 2.00 Game Loader for 1.50 (gta version)
-------------------------------------------


Before using this program, please read the following:

- This loader requires the iso of the game to run, do not use the iso if you don't have the original umd.

- You will need:
*umd emulator,
*umdgen,
*DecryptPRX (which is a modification of psppet's psardump tool.)
*firmware launcher or psardump (needed for 2.0 firmware files)

CREDITS :
---------

THANKS TO :

- Tyranid for his beautiful psplink tool
- PspPet for his psardump known of all
- All pspsdk team
- umdgen and umd emulator authors


Iso modifying :
---------------

You will need the GTA iso to continue, do not ask me where to get it.

Once you have obtained the iso, it is necessary to extract all the files from the iso (use the umdgen program for this).

Copy the DecryptPRX folders to your memory stick.

Next, place the "PRX2_0_0" folder, located in the GTA iso (PSP_GAME\USRDIR) in the "crypted" folder of your memory stick.

Execute the DecryptPRX program. DecryptPRX will "fix" the prx files.

Rebuild the iso with the new files inside the PRX2_0_0 folder.

Your GTA iso is ready.



Firmware 2.00 installation :
----------------------------

You will need to decrypt firmware 2.00 into a file format, use firmware launcher to accomplish this.

Once you have the files, copy the mphgameloader folder to the root of your memory stick and copy flash0 (kd, vsh...) and flash1 folders inside.


Loader installation :
---------------------

Install the loader (MPHGAMELOADER) like any other psp application (PSP/GAME/).


You will have the following structure of folders/files :


Memory stick
|
|- mphgameloader
|
|- mphloader.prx
|
|- flash0/ (with sub folders and files)
|- flash1/ (with sub folders and files)
|
|- PSP/
|
|- GAME/
|
|- MPHGAMELOADER
|- MPHGAMELOADER%
...


Launch gta :
------------

Run umd emulator and choose the gta iso.

Launch MPHGAMELOADER


Welcome to the gta world.


MPH