Just as he stated, Dark_AleX has just released the 1.50 kernel add-on for
custom firmware 4.01 M33. Now all you phat owners may enjoy your 1.50 kernel-needing homebrew games and apps.
The installation instructions are simple. Just copy and paste the the installer folder into your /PSP/GAME4.XX folder and also place the 1.50 firmware eboot inside of your PSP's memory stick root. Be sure to have the eboot named 150.pbp.
Not much else to say but that Dark_AleX gives a small sorry for the delay, since his servers weren't working yesterday. But no need to apologize DA, we love you anyway.
You can find the download below. And please remember this is for phat PSP's only. Have fun!
Official 150.pbp Download: Here