I don't have the option to use media server on PS3 the media server setting is invisible here for me what I do to get it back I'm on version 4.84 dex :
How to Convert a Jailbroken PS3 from CEX to DEX with Rebug CFW - YouTube
PS3 CFW CEX DEX REX difference - YouTube
How To Jailbreak, Install CFW & Convert to DEX on PS3 (4.88) - YouTube
PS3 - Can't sign in to PSN after converting to dex? Getting sign in errors? AUTO Set "eid5" trick - YouTube