i can say 2.1 fixed this problem for me too and my plantronics 925 now works again.
to shinanganz, i'm glad you haven't had the problems the rest of us have had. but don't be insulting and imply this is our fault. this was a well documented "change" with the 2.0 software. my headset couldn't be used for visual voicemail (it wasn't even an option) after the update. worked fine since i got the iphone with the initial firmware, and worked great thru until this update. then it didn't work anymore. i can assure you, I didn't break with the update. so it must be the software that did it. :/
all i can say since 2.1 is yay. this has been a great update. things are working, working well and a few new things were added.