PRXdecrypter 2.4 for more compatibility and stability .

This is what the developer had to say about this psp homebrew application PRXdecrypter 2.4

Can decrypt/decompress/extract:
* firmware modules from official firmwares (up to 6.20)
* updater modules from official updaters, including obfuscated ones
* official updater DATA.PSP
* reboot.bin and reboot_02g.bin from all retail firmwares
* EBOOT.BIN and modules from all retail games (up to 6.20), and non-retail/testing EBOOT.BIN files
* M33 custom firmware modules
* RLZ files
* KL4E files
* meimg.img and me_sdimg.img
* demos and game sharing DATA.PSP files
* index.dat
* 1SEG.PBP