PSX games not working with PS2

[MissFacetious]

Recently I went through all my PSX backups on my PS2 and found that not all games would work.

I am going on the assumption that media is not the issue because backups were burned in duplicate with verbatim and imation cd-rs and aren't scratched.

The games in question are Legend of Dragoon & Breath of Fire 4. I believe Legend of Dragoon doesn't work because it has a copyright protection on it, and the original PSX patch is installed on the disk but doesn't work on the PS2. Breath of Fire 4 works on the PSX even without a patch, but not on the PS2.

For any ideas or if you've seen this problem before, or maybe other games you've found that don't work, I would love to hear any suggestions.