What you have read on the forums is correct. The first step in resolving those issues that you have described is to have the vehicle radio and navigation system updated to the latest software/ firmware versions. This is done by your local BMW center. They usually charge around 1.5-2.0 hours labor to perform the programming; so depending on the labor rate is around $200-250. All of the vehicles control modules will receive up to date software levels (you can compare this to updating a program on your home pc!).
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No, an independent repair shop will not have the necessary equipment with the latest updates to program the vehicle. The vehicle is programmed over a BMW factory server that an independent shop would not even be able to purchase.
There is no way to tell if your vehicle has the latest updates unless you have a dealer bmw scan tool. With audio concerns/ especially the crackling noises you are experiencing; 9 times out of 10 it is a software issue. I would definitely start with the vehicle programming.
The ask is essentially the radio control unit... it gets reprogrammed with the update; and the most bus is the fiber optic line that connects the control units on the audio system allowing them to communicate with each other.