Since rebooting on your infotainment system only happens in sub-zero temperature, it has to be hardware related. Software updates won't resolve the problem. Many new CX-9's have rebooting problem on their similar infotainment system but that's not related to cold temperature but the separate tablet display unit is the culprit. The problem for you is, as the weather is getting warmer, it becomes harder to duplicate the problem. I'd suggest you making a video when the rebooting happens again in your next occasion of sub-zero weather, and send it to Customer Experience Center of Mazda North American Operations. Even if you can't make it happen again due to the warmer weather, you still call Mazda to create a case with a case number and ask them to replace the infotainment unit if they're willing. Your 2016 CX-5 may run out of the new car warranty in next winter like mine, so you need to think ahead as your infotainment system rebooting can only happen in the winter time.