If you own a (SuperSlim), you cannot install full CFW. Your only option is PS3 HEN.
Here’s a concise, practical review of using on a PS3 with HEN (rather than full CFW).
Every Feature of MultiMAN Explained! MultiMAN Full Guide For Dummies
Inside multiMAN, go to Settings > System. Ensure is set to Standard. For HEN users, do not use Cobra mode (that is for CFW). Standard BDEMU works flawlessly with HEN 4.89 to emulate a real blu-ray drive, allowing games like Red Dead Redemption to boot.