Apparently same problem exists on e46. the problem is a circular plastic mount about the size of a half dollar that holds knob breaks at one or more of 3 screw hold down points. For.the e46 but not.the e70 there are diy youtube videos and Bavarian auto sells the mount which would seem worth $5 for $30 which is still way cheaper than the whole radio.
One of the posters here says for about $65 he may be able to fix my problem. I would need to send my radio. What worries me is I might get a radio which doesn't even turn on in return?
I likely will send him my radio