Playing on your PC or phone? The process is nearly identical, but the destination folder changes based on your device: Documents\PPSSPP\PSP\SAVEDATA\ Android: Internal Storage/PSP/SAVEDATA/
The game automatically saves your progress to a Memory Stick Duo whenever you complete a challenge, purchase or modify a vehicle, buy a new house, or change system options. save data test drive unlimited psp
You can find these "solid" 100% save files on community hubs like Installation Steps: Connect Your PSP: Playing on your PC or phone