I used to get BAD echo with my Iphone 3g and I kept trying to fix it . Went to dealer , phoned apple etc... NOTHING worked...
About 2 updates ago when I paired my Iphone and uploaded the new update , my problems went away and its working amazingly well now.
Really weird if you ask me but apple was blaming BMW and BMW was blaming Apple.
2012 E92-M3 Space Grey on Fox Red, DCT
2011 B8 S4 S-Tronic , Black on magma red