menuconfig U_BOOT bool prompt "build U-Boot bootloader for target" config U_BOOT_VERSION string depends on U_BOOT default 1.2.0 prompt "U-Boot version" help Enter the Uboot version you want to build. Usally something like "1.2.0" config U_BOOT_CONFIG string depends on U_BOOT prompt "U-Boot config target" help The U-Boot make config target. Usually something like "yourbox_config". See Uboot's main Makefile for possible configuration targets.