Hi,
My point is not to criticize a product that I used and enjoyed for a while. However you need to know the following, if you come across the same issues:

My K-bus turned dead and alongside pretty much every convenience feature: instrument cluster, windows, wipers, radio, aircon, soft-top, nav screen, etc.

I first thought it was a bad multimedia harness, but ended up costing me £300 to have BMW diagnose a faulty Dension IceLink which shorted the K-bus to +12V.

Luckily no HW was damaged, removing the Dension IceLink solved the problem. Dension themselves admitted the device was dead but still have not offered to replace it after its warranty nor participate into the costs induced.

So if you have the same symptoms, the IceLink could be a good direction to dig.