One can use the format_sd.sh script we provide with our images, to format the SD card which can be used with update procedure as well as for booting.
Assuming /dev/mmcblk0 is the /dev node pertaining to the SD card
./format_sd.sh -f -d /dev/mmcblk0
“-f” option will additionally copy the rootfs into the second partition.
From uboot, one can then boot from the SD card by executing “run sdboot” command.
If you would like this to be the default, add “run sdboot” as the first option to the “bootcmd” uboot environment variable which by default would be “run ubiboot” for booting from NAND flash.
Also note that the script would put the relevant binaries in the first partition of the SD card which can be used for the update process.