How to get PSP games to work

[sprocket314]

Pi Model or other hardware: Raspberry Pi 4B in a Picade
Power Supply used: Standard universal power supply from the Picade
RetroPie Version Used (eg 3.6, 3.8.1, 4.1 - do not write latest): 4.8
Built From: Official Retropie image from the website
Controller used: Picade joystick plus arcade buttons
Error messages received: When trying to run an .iso file, it goes dark, nothing happens and it returns to Retropie
Guide used: the PSP section in Retropie's website

Hi there, I'm trying to get PSP games to run in Retropie. I have installed the package (I actually installed all the optional packages), I made sure that the es_systems.cfg has the psp config. I can see the PSP menu in Retropie's splash screen. I got a PSP .iso file (two actually) in the /roms/psp/ folder and when trying to run any of the two .iso files, the screen just turns black briefly and then goes back to retropie.

I must say that the original PSP rom came in a .rar file and it was much much larger than when I extracted the rar files until I got the .iso file. So the .rar file would be 1.2GB and then the .iso was 18MB. Is this normal? It is my first time doing this. I don't think the .rar file would be a valid format for PSP or am I wrong?

How do people that successfully run psp roms do it?

Many thanks for your help.
Best regards. I'm doing this for my daughter. She likes LocoRoco.

[windg]

It looks that your rom file is corrupted. Do you have issues with other psp games ? If you can try again from a different source.

[sprocket314]

@windg That's a good suggestion. I'll try a different psp game to get it to work. This is my first time with psp roms.