[beagleboard] eMMC backup

The easiest/quickest is of course "dd":

sudo dd if=/dev/mmcblk1 of=${HOME}/mmcblk1.img

But for one of my customers i have another 2 part script in the works:
"backup eMMC & auto flash eMMC on bootup" but i'm on the road this
week, so it probally won't show up in my tools/scripts folder on
github till this weekend..