Try changing the "ISO Video Mode" in the VSH menu (press Select on the home screen) to Sony NP9660 M33 Driver Roster not updated:
: Official development for the PSP ended with SmackDown vs. Raw 2011
This is usually caused by a corrupted download or an incorrect ISO/CSO compression ratio. Try re-extracting the RAR file. If that fails, you may need to change the "Rendering Mode" in PPSSPP settings from Buffered Rendering to Skip Buffer Effects (or vice versa).
If playing on a real PSP console, connect your device to your computer via USB. Copy the .cso file and paste it directly into the ISO folder located at the root of your Memory Stick.
Over the years, several notable fan mods have been released. The search term Wwe 12 Psp Cso.rar often points to files like or "WWE 12 PSP EDITION (2014/Eng)." These mods, shared on forums and file-sharing sites, represent the community's dedication to bringing the WWE '12 experience to the portable platform.
Download and install the latest stable build of the PPSSPP emulator.