There is an option for expand storage capacity up to 128 GB with microSD card. (gadgetfolder.com)
There is a microSD Card slot to expand the storage capacity up to 32 GB which is great for people who loves to own and watch a lot of movies. (ubergizmo.com)
It is likely that the Mate S2 will also have a microSD card slot that can be used to expand the storage capacity of the device. (techtimes.com)