F30 radio DOES supports MTP based USB android devices
so this tends to not work on a lot of cars , and even computers. I had read the F30 didn't support the galaxy nexus which is MTP (usually talking about 2012 model year cars, so maybe needs a firmware) but tried it anyway.
Most newer android phones when they are connected by USB either the internal memory or all the memory is read as an MTP "media device" not a USB flash drive (usb mass storage). On older cars that have USB flash drive reading they generally cannot read MTP.
I tried my new droid razr M on the F30. Razr M lost its USB mass storage with the upgrade to android 4.1 from 4.0. Anyway it works great!
I know this doesn't work on E90 cars, but it does on the F30. so if you have a galaxy S3, or razr, or galaxy nexus , nexus 4 or countless other android devices you can play them via a USB cable in the arm rest and control it via iDrive like any other device instead of having to use say A2DP (especially nice if you know you dont have A2DP which is only on BMW assist like me).
So FYI to anyone who wanted to know.