PS Vita system update 3.10 may fuck your 32GB memory card.

Some users on the PSN forums has reported that the last update bricks the 32GB memory cards.
After the update, the device won't start with the memory card inserted.�

http://community.us.playstation.com/t5/PlayStation-Vita-Support/Update-3-10-Bricked-My-PS-VITA/m-p/43214930

http://www.gamefaqs.com/boards/620272-playstation-vita/68877226?page=9

So far for now, 16,8 and 4 GB memory cards seems to work fine.