Last year I retrofitted my 2003 530i with the 16:9/MKIV nav system. The car is high obc and previously had the cd player. I am running software v27 and had taken it in to the dealer to have it coded which of course caused me to loose the split screen on radio function. I know of the downgrade/upgrade trick to get it back but on taking the car in the other day I noted to the dealer that on my last visit they coded the computer and it lost my split screen. I then gave him some background and asked that it just be noted in the service record the results of the coding...

Well... this is the second day they've had the car and they are apparently really trying to figure out why this happens so they can fix it. They seem pretty determined. At one point I had read something about the underlying cause to this problem but can't seem to find it. Can anyone point me in the right direction or pass on any info that I can pass to them to point them in the right direction? I figure if they can figure it out it will help us all out. Thanks.