test -n ${interface} || setenv interface mmc
test -n ${drive} || setenv drive 1

setenv set_blkcnt 'setexpr blkcnt ${filesize} + 0x1ff && setexpr blkcnt ${blkcnt} / 0x200'
setenv update_uboot 'fatload ${interface} ${drive}:1 ${loadaddr} u-boot.imx && run set_blkcnt && mmc dev 0 0 && mmc write ${loadaddr} 2 ${blkcnt}'
echo 'enter "run update_uboot" to update the uboot'