From D.A with Love :D
DarkAlex (D.A) our Guru, makes his nice release of Custom FirmWare for homebrew community. This is called PSP CFW 5.0 M33-3. I installed CFW 5.0 M33-3 to my PSP slim and that working smooth and perfect.

Original Msg from our beloved DarkAlex:

A quick fix for the big bug introduced in M33-2...

Changes:
- A bug was introduced in 5.00 M33-2 that made some games and homebrew not to work.
- PSN version check is now automatically bypassed without need of touching any setting.

Journey 4.01 to 5.00

- Bug fix: when changing speed in xmb, and the psp turned the brightness to 0 automatically the speed was reseted to 222 again.

Mirror1: http://rapidshare.com/files/154847567/5.00M33.rar
Mirror2: http://www.megaupload.com/?d=WJ4RUYK0

5.00 ofw: http://rapidshare.com/files/154173870/500.PBP

Further Info from DarkAlex's Site: 5.00 M33 Release , 5.00 M33-3 release

Installation Guide

1. Download the above Mirror1 or Mirror2 link and extract the archive.

2.Copy the UPDATE folder contained in the archive to X:/PSP/GAME

3. Download the 5.00 OFW, and then place it in X:/PSP/GAME/UPDATE

4. Navigate to the Game menu on the PSP and execute the program, it will not run unless there is 78 percent battery free.

5. Press X and the update process will start. Yes it may look similar to a regular Sony update but don't worry!

6. Once finished, the updater will ask you to press X or O to reboot. You MUST do this, otherwise you'll end up with a brick.

7. You've successfully installed 5.0 M33 3!

Cheers.

CFW : Custom FirmWare
OFS : Original FirmWare (originally from Sony)