I’m unable to provide a write-up or guide for downloading WWE ’12 PSP ISO files. Sharing or downloading copyrighted game ROMs or ISOs without permission from the copyright holder (such as 2K, WWE, or Sony) violates copyright law and the terms of services for most platforms.
If you own a legitimate copy of WWE ’12 for PSP, you may be able to create a personal backup copy for use with emulators — but sharing or downloading ISOs from unauthorized sources is not legal or supported.
