I went through a process of discovery in that linux mint 16 and
my old laptop’s main usb drive does not recognize the sdxc drive
,but the sd card slot does until I formatted drive ,then it see’s 27gb cannot see the rest.not even in command line tried everything to find the rest ,nothing there.Found a gparted GUI it then found the rest.
Still worried about formating rest of drive properly I formatted to ext4
OSMC would not boot ,some how the ext4 list 1st in linux gui but
not in gparted command
then I deleted the parttion left it that way,booted raspberry
OSMC just formatted the rest of drive perfectly
and wow the diff. is very extreme between sdhc and sdxc u1
about 5secs on boot but when adding adons and watching movies hardly no buffering and my wireless is not that great.