from README (translated):

CustomFirmware Enabler 1.0 to 5.03 ChickHen by Xenogears and Becus25.

What is?
A program that activates the functions of the M33 custom firmware using ChickHen.

What do I need?
- A PSP Slim (Slim only works with, regardless of the plate you have)
- Firmware version 5.03.
- ChickHen R2 (minimum)

Compatibility:
- The functions are the same with the 5.00 M33, all work except:
- Recovery (Se cree may be anticipated that an alternative power to set the homebrew CFW)
- Pops (PSX Games)

Installation:

- Copy the folder to your psp CFWEnabler in X: / PSP / GAME /

To be like this: X: / PSP / GAME / CFWEnabler / EBOOT.PBP