Custom Firmware such as 6.60 PRO-C, 6.61 LME, or Infinity.
Note that while some sites like Minecraft PSP 3.2.1 | Распечатай и играй may mention the title, they often refer to tabletop or print-and-play versions rather than the digital handheld file. minecraft psp 3.2 1 download
The project is split into different versions based on your PSP hardware: Custom Firmware such as 6