Here is PRXdecrypter 2.4 – a minor update, with all the keys up to 6.20 courtesy of bbtgp, who spent many hours reversing to get them, whereas I just spent 10 minutes updating my source code.

Changelog:

2.4 –> 2.4a
- New EBOOT.BIN key added – fixes “tag error 0×2E5E10F0″
- Can extract the nand_updater/lfatfs_updater from old updaters again
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