[beagleboard] What kind of MicroSD card for BB XM?

You can giveThe the partions mount points like "boot" for the first partion and "rootfs" for the second then you can use /media/boot and /media/rootfs. If you are trying to use the demo image I assume its the RC image just use the script provided in the folder it is very simple to use. You can also try /dev/sdb