I've been playing around with the Shield for a while now, and would love to flash the boot image to native storage along with the contents of the SDcard. It looks like 'fastboot flash boot \path\boot.img' should work as long as I choose the proper image to boot from the emmc. However I'm having difficulty finding out how to move rootfs to the emmc. I'm wondering if there is a straight forward way such as 'fastboot flash rootfs' ? Any help would be greatly appreciated.