Things we need for NiChrome.
To get an image, for both KERN-[AB] and ROOT-[AB],
Build the usb tool: (cd usb && go build .)
Plug in a chromeos-formatted USB stick (TODO: how do we correctly do this formatting)
./usb/usb -fetch=true -dev=/dev/your-usb-stick
e.g. ./usb/usb -fetch=true -dev=/dev/sdb
usb will default to /dev/null, which makes it easy to test it. You can also run travis.sh to test.
You can skip the -fetch=true on second or later runs of usb.
This defaults to writing the A image (partitions 2 and 3). To use the B image, invoke usb with -useB=true