I have also faced same issue when tried to do menuconfig for u-boot-imx (Cmd used: bitbake -f -c menuconfig u-boot-imx) the command error appeared as no rule to make target 'menuconfig'.
Then used command as suggested in this discussion - bitbake -c clean u-boot-imx && bitbake u-boot-imx.
But that does not open the menuconfig UI. Please help.