Sony built a PS1 emulator into the PSP. With CFW, you can convert your own PS1 discs (using PSX2PSP ) and play them perfectly. The 6.61 version includes "Popsloader" to mimic older PS1 firmware for problematic games.
. Version 6.61 is the final official firmware released by Sony, providing the best baseline for game compatibility and system stability. Choosing Your Custom Firmware While multiple options exist, psp custom firmware 6.61