Origins and Structure Save data on the PSP was simple in concept but vital in practice. For Underground Rivals, each save file tracked a snapshot of a player’s campaign: unlocked cars, custom parts, visual mods, currency, current event progress, and driver stats. Unlike modern cloud-backed systems, this data lived locally — a small binary file tied to your PSP’s user profile and the game’s title ID. That intimacy made the file both precious and fragile. Lose it, and entire nights of grinding — beating rival crews, collecting cash, and tuning engines — could evaporate.