Liquidzigong has cracked key tag 0?2e5e10f0. This key is commonly found in PBOOT.PBP files. Say what—PBOOT.PBP files?! Yeah PBOOT.PBP files are game patches. Now you can decrypt whatever patch, apply it to the appropriate game, and continue on keeping on.

How:

   1. Open the PBOOT.PBP file using PBP Unpacker or some similar tool.
   2. Unpack/extract DATA.PSP and PARAM.SFO.
   3. Rename DATA.PSP — which is usually encrypted with 0?2e5e10f0 — to EBOOT.BIN.
   4. Copy EBOOT.BIN to ms0:/enc and run PSPCipher like any other homebrew.
   5. Open your game ISO with WQSG_UMD.
   6. Replace EBOOT.BIN with the newly decrypted EBOOT. (If you’re using Prometheus then name it EBOOT.OLD.)
   7. Replace PARAM.SFO with the one from PBOOT.PBP.
   8. Save your ISO and try it out.

This has been confirmed working with the latest God Eater v1.01 patch.

Description:
Liquidzigong's PSPCipher decrypts PSP game patches (PBOOT.PBP files). PSPCipher is currently the only tool that can decrypt key tag 0x2e5e10f0. Unpack the PBOOT.PBP file extracting DATA.PSP and rename it to EBOOT.BIN. Copy EBOOT.BIN to ms0:/enc and run PSPCipher to decrypt it.

Download: PSPCipher.zip