megagames.com -> psx utilites -> gameshark cd -> enter these codes

D01BF6F4 023A
801BF6F6 1000
D00FC08C 023A
800FC08E 1000
============
D01BF664 FF52
801BF66E 1000
D00FBFFC FF52
800FC006 1000

try all 8 first, if that doesnt work, try the first 4, if that doesnt work, try the second 4, if that doesnt work, get a stealth 4 mod chip from mod-chips.net