[U-Boot] Need of MMU in uboot level

Hi, We are using exynos 4210 based odroid-PC board.I have gone throgh the uboot code in which it is enabling MMU.I want to know why do we need to enable MMU in uboot level.I came across this question when i was trying to use "go" command in uboot which does not seem to be working.

Thanks & Regards, Shabbir.