It seems to be there available to download.

Here are the release notes.

BMW MediaBridge
Version Number: 4631
Release date: 7-19-2011

Changes and improvements
---------------------------
- Improved wakeup detection to resolve drop-off issues reported in older cars
- Added additional resolution to default audio level setting
- Improved 6th gen iPod nano detection

- p

I did the 4631 the other day. So far so good. Hopefully this is the fix! If so, I'm very happy w the MB1500

I cannot get any sound from my MB1500. I've tried everything but its silent.
the Nav display shows the iPod song name, so at least that part is working ...
any hints anyone ??

I have a 2008 X3 with the wiring connected in centre console

Has your car got DSP?

got it working ... needed to match up the correct wires between the console and the HU. all good now

(no DSP)