Here is DOOM v1.4 for PSP Slims running custom firmware. It may also run on PSP fat. This version actually boots up and works, playing right now. View readme for more info.
1. extract rar
2. copy DOOM folder to PSP/Game
3. enjoy!
Download:
http://www.divshare.com/download/4639311-d40
While playing hold triangle button, and press any direction on the D-Pad to activate cheats!
Also hold triangle button and press right or left bumper to change weapons.
