It's part of the SD specification. See section 4.3.7.1: http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf http://www.sdcard.o

It's part of the SD specification. See section 4.3.7.1: http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_Physical_Layer_Spec.pdf http://www.sdcard.org/developers/tech/sdcard/pls/Simplified_... There are WP7 devs that are poking at this problem as well: http://forum.xda-developers.com/showthread.php?p=9247202 http://forum.xda-developers.com/showthread.php?p=9247202