Top got stuck, mechanic was able to get it down but said the computer had to be reset and only a dealership could do it. The dealer wants $800! Is this correct and normal?
My exposure to BMW’s convertibles have been on their 325 series, two of which were too old to even have power tops. On those 325ics I’ve had that had power tops there was a way to disconnect the power mechanism from the top hidden under the rear seat. I don’t know if that exists on your later car, and it is not suggested as a permanent fix. It may be what your mechanic did to get your top down.
I would suggest asking your question on this BMW forum: http://forums.bimmerforums.com/forum/index.php Understand that there a a FEW guys who post there who know their BMWs but many have never had dirt under their fingernails, and would be inclined to just pay Fritz his $800 and be done with it. Such is the nature fo the marque.