God Eater 2 - NPJH50832

[Hykem]

So how do we decrypt the files on psp?I want this game to work on jpcsp since lately my analog stick is going crazy

In theory, you should be able to decrypt SPRX files with PSPCipher. Try editing a SPRX file with an hex editor and you will see two headers: PSPEDAT (used for EDAT encryption) and ~PSP (used for PRX encryption, should be at offset 0x90).
Remove the PSPEDAT header and try decrypting it. I'm not sure if this method works for all SPRX files (there could be an extra encryption layer after processing the PRX), but I've already tested a few that worked.
I'll add the ability to load decrypted SPRX files externally so this can be properly tested.