The SD card has nothing to do with updates. Updates require enough INTERNAL space to work. You will need to uninstall some apps and reinstall later. The Internal memory is split into 2 parts. 1 is for system files and apps (this is the area that needs more space) and then there is the area for files, documents, videos, pictures. The apps are the area you should clean up first, then, if need be, the other media files. Most updates are 1GB average so, you don't have to have much space. Also, going into the Settings menu then to Storage and tapping on Cache to clear it out might help.