Many "working" versions found online are actually heavily modified versions of GTA: Vice City Stories (VCS) that swap assets like textures, player models (CJ), and portions of the map to resemble San Andreas.
The PS2 is notoriously difficult to emulate even on modern gaming PCs. The PSP, with its 64 MB of RAM (half of which was reserved for the system), stood no chance. Early attempts at converting San Andreas to PSP resulted in slideshows: 3-5 frames per second, sound that stuttered like a broken CD, and a draw distance that made the fog of Silent Hill look like a sunny day. gta san andreas psp eboot pbp upd work
If you own a PSP Go and a PS3 with GTA San Andreas (PS2 Classic version), you can use Remote Play. It’s laggy but functional. Many "working" versions found online are actually heavily