Place of Origin : Shenzhen,China

Does Brave 8 have an upside-down function/auto rotate?
Yes. Brave 8 has a G-sensor. After enablement, it will rotate and pull down automatically. Go to preferences?gyroscope.

What's the maximum micro-SD card size compatible with this 4k ultra hd underwater camera?
The maximum storage is 512GB. It requires a U3 micro-SD card or higher, otherwise, the low card speed will affect normal use.