I've had a similar experience to others here. 2015 85D. Not interested in the MCU2 upgrade, as my car operates well, even though I have the same occasional sluggishness and non operational web browser as every other MCU1 owners, as well as some reboots.
When the daughterboard upgrade was first announced, I called the SC to proactively have it replaced, and was told that they aren't doing it proactively unless you want to pay for it. WIthin about a month, my IC screen developed the dreaded bubbling goo, and I had several additional reboots. Scheduled to get screen replaced, and daughterboard replaced. Received several requests for date / time of reboot. I know I have no basis to wonder about this, except as others have noted, if there is something in the logs that they are searching for, cant they just "search" for it? Generally when my reboots have happened I'm driving, and cant note the time and date. I did get one reboot date and time, which I reported to them via text.
When I picked up the car with the replaced IC screen, there was a note in my invoice that they had ordered the daughterboard and would replace. Not sure if it was my persistence or something they noted when they had the car in. My advice to others would be:
1. Don't try to get this done proactively if you aren't experiencing issues - they seem resource constrained and they likely want to push proactive replacement (or have you pay for them) due to lack of supply.
2. Give them as much info as you can, but be calmly persistent in asking for the issue to be resolved if you are having symptoms.
3. My car has been perfect for years - never experienced a screen or reboot issue, but went downhill pretty quickly in the number of reboots.
