I have been backing up the entire disk of my Surface Pro 4 (comes with 3 partitions) to an external USB disk hooked in via a USB 3.0 hub (which connects to the SP4 lone USB port). Recently I sent my unit back to Microsoft due to some video artefact problem and they sent me a replacement unit. Turns out trying to restore my backup images to an SP4 is much more troublesome.
Since these type of tablet models don't come with a built-in optical drive, I created bootable media with a USB thumb drive. The thumb drive is connected to the same USB 3.0 hub. It can boot the Acronis launcher, so working through the hub is no problem. However it complained that it could not detect any hard disk at all, neither the SP4's own internal disk nor my external ones. So I am stuck with no avenue to restoration.
Has anybody ever successfully restored entire disk images for Surface Pro units?