problem playing ps2 dvd+r backups

[snuff1175]

I have used clone cd to copy ps2 cd roms, and then used the knife method along with game shark 2 to swap the disc and play the game. It boots fine. I just bought a dvd burner. I used nero to make a copy of a dvd game, but using the same swap method, nothing happens. I've looked at both the original and the backup files on my pc and they look identical. Is it because I don't have a mod chip. If so, what would be the best modchip to by. I have a version 1. Am i supposed to patch the games before I burn them?



Thanks to anyone that can help!!!

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