using a backedup gamesharK?

I have an older gameshark and it's incompatiable w/ newer games...i.e. GT4.... my friend wanted to get full money and my older gs doesn't have any codes for it, so I remember I had an ISO of gs2 v4.1 which has codes and I was wondering how do u load a backed up GS via swap method? anyone have any ideas? since the gs disc is a psx cd, I used the swap method and put in a psx original w/ a bigger toc then the gs and it didn't work, since i have an usb modchip, i tried booting off of it too, didn't work....tried everything... anyone have any ideas? thanks alot.