How to update uboot and kernel in the running time

I used the command :sudo BOARDID=3448 BOARDSKU=0002 FAB=400 FUSELEVEL=fuselevel_production ./build_l4t_bup.sh jetson-nano-emmc-smpsq mmcblk0p1

we used emmc,the command error:

Creating update payloads for Jetson-3448-400-0002–1-0-jetson-nano-emmc-smpsq-mmcblk0p1 board …
ls: cannot access ‘multi_signed/jetson-nano-qspi-sd/*.bct’: No such file or directory