Choosing a bootloader (BPI-R2)

How can I select/configure a bootloader during the build process? The "boot loaders" area in menuconfig is always disabled for me. Specifically, I'm trying to follow these directions (http://wiki.banana-pi.org/Getting_Started_with_R2#OpenWrt_On_SD_.26_Emmc_Steps), but I'm curious for other platforms also.

you can ask this question in bpi-r2 forum. :grinning:
http://forum.banana-pi.org/c/Banana-Pi-BPI-R2