Hello, I also read that Assassin Creed corrupted some user's HDD, but I don't know how far it's true. I find it strange, but better keep one just in case. Some games require that there is effectively a game (or any disc) in the drive. I don't remember any "Emulate BD Rom" option. maybe it's in the newer version ? (4.0+) Or maybe you are talking about "BD-ROM Emulation" (I guess that's the one you are referring to). This setting is required to play games from HDD (internal or external). You don't need it if you play from burned BD media. It's the option used to select the payload you want to use to patch your console's memory. if you have BDEMU v2 and are using a custom firmware without native payload then you will have 3 choices : None / Default (PSGroove) / Hermes Hermes payload is needed for few features, such as playing games with 4G+ files on external and caching only big files on internal.