Steam Deck: This is currently the best way to play the full, uncompromised version of GTA 5 on a handheld PC. Final Verdict
If you want a genuine GTA experience on a handheld device, there are better alternatives than searching for non-existent PSP ports:
PSPISO Club and similar sites are third-party platforms that host ROMs and ISO files for the PSP. When you see "GTA 5 Updated" listed on these sites, you are usually looking at one of three things: pspiso club gta 5 updated
GTA: The Trilogy – The Definitive Edition: Available on Nintendo Switch and mobile devices (Android/iOS).
HUD Overlays: A mini-map and weapon wheel that mimics the GTA 5 aesthetic. Steam Deck: This is currently the best way
New Radio Stations: Modern music tracks added to the game files. How to Safely Play GTA on the Go
GTA 5 PSP Download: The Truth About PSPISO Club and Mobile Ports HUD Overlays: A mini-map and weapon wheel that
If you do find a legitimate modded ISO (usually based on GTA: Vice City Stories), the "updated" tag often refers to: Character Skins: Playing as the Los Santos trio.