PRXdecrypter 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 some nonretail/debug EBOOT.BIN files
• M33 custom firmware modules
• RLZ files
• KL3E/KL4E files
• meimg.img and me_sdimg.img
• demos and game sharing DATA.PSP files (not all of the new ones)
• index.dat
• 1SEG.PBP

Changelog:

• Decryption error for an old key, tag 0x4C940AF0, fixed.
• Decryption key added for pops_04g.prx from 6.XX firmwares - tag 0x457B1EF0
• Slightly more information when encryption is likely to fail (SHA-1 check warning)
• NOTE: key for tag 0x2E5E10F0 does not appear to be working due to a new encryption method. I'll look into it.
• New EBOOT.BIN key added for tag 0x2E5E12F0. As above, might not work.