Okay, now I have tested a bit The results are as follows; if you set G_EXPORTED_PARTITONS="/dev/mmcblk0", you will get all partitions exported. if you set G_EXPORTED_PARTITONS="/dev/mmcblk0p1", you will get just one partition exported. if you set G_EXPORTED_PARTITONS="/dev/mmcblk0p1,dev/mmcblk0p2", you will get both partitions 1 and 2 exported. (the driver will contain 2 different luns in this case, one for each partition) Now this above is what happens on Linux. My guess is that on Windows the 1st and 2nd behave similarily, only the partition 1 gets exported, but the 3rd case would export both partitions correctly.