If you absolutely need your fix, you're better off using modern hardware:
from users wishing for a PSP homebrew version, but no stable, standalone "paper" or release for the original PSP hardware currently exists in a mainstream capacity. Paper Representation subway surfers for psp
Utilizing power-ups like the hoverboard and magnet could significantly ease progression through difficult sections. These, along with coins and score multipliers, were crucial for achieving high scores and unlocking new content. If you absolutely need your fix, you're better