(BeagleBoneBlack)ubuntu@localhost:~$ ./uboot-env-armhf /boot/uboot/uboot.env print|grep snappy
loadfdt=load mmc ${mmcdev}:${mmcpart} ${fdtaddr} ${snappy_ab}/dtbs/${fdtfile}
loadinitrd=load mmc ${mmcdev}:${mmcpart} ${initrd_addr} ${snappy_ab}/${initrd_file}; setenv initrd_size ${filesize}
loadkernel=load mmc ${mmcdev}:${mmcpart} ${loadaddr} ${snappy_ab}/${kernel_file}
snappy_boot=if test "${snappy_mode}" = "try"; then if test -e mmc ${bootpart} ${snappy_stamp}; then if test "${snappy_ab}" = "a"; then setenv snappy_ab "b"; else setenv snappy_ab "a"; fi; else fatwrite mmc ${mmcdev}:${mmcpart} 0x0 ${snappy_stamp} 0; fi; fi; run loadfiles; setenv mmcroot /dev/disk/by-label/system-${snappy_ab} ${snappy_cmdline}; run mmcargs; bootz ${loadaddr} ${initrd_addr}:${initrd_size} ${fdtaddr}
snappy_cmdline=init=/lib/systemd/systemd ro panic=-1 fixrtc
snappy_stamp=snappy-stamp.txt
uenvcmd=run snappy_boot
snappy_ab=a
snappy_mode=regular