Comment 9 for bug 1579767

aha, so you are not having any of teh required snappy_* vars set at all ...

see http://bazaar.launchpad.net/~snappy-dev/snappy-hub/snappy-systems/view/head:/pi2/boot-assets/uboot.env.in

you want the "loadfiles" bits (adjusted for your system (specifically the fdt loading part i guess))
as well as all the snappy_* vars (you can just copy/paste these)

then point your actual boot command to "run snappy_boot"