If you Boot your console without the SD card inserted and Launch Mii Maker App, does your console freeze , or does it just load Mii Maker App normally? ( if your system freezes without the SD card then your dealing with some sort of system corruption ) .. if Mii Maker loads normally, then you're dealing with probably just an SD card issue ( maybe the SD card has reached its end of life ... maybe it needs a fresh reformat (FAT32) along with new fresh Tiramisu files etc. - most likely some sort of SD card file system corruption) ... )