I was able to play GT4 and Spongebob's Atlantis Squarepantis. In the beginning I was having a problem even starting the games, but then I realized that instead of using the actual PS2 ID of the game I should just rename the PS2 ID as PS2U10000
Now I know there is a way to play different games without using the same ID, but I am too lazy for that right now. So If someone is having problems right now, then he should rename the title to PS210000 and it would hopefully work.
I only had to using rap files once. Not twice, not thrice, just once. I do not know how to make Package, even with the PS3Tools, I forgot, so I just copy the game to a USB, and if the game's bigger than 4 GB, then I just use Multiman's PFS Toggle to NTFS and then copy the game to the directory.
I can't believe Sony allowed PS2 playback only now! Keeping the information all to themselves! And charging for the PS2 games that we already payed for is not right! All they do is modify a few files and charge us 20 dollars. Way to go Sony...