LinkIt boot from SD card

Hello all,

I have a LinkIt smart 7688 with my own Openwrt build on it. I would like to be able to boot my board directly from a SD card in ext4 instead of the default memory.

I believe all I would need to do is add support for MMC devices and ext4 filesystems to the u-boot bootloader; however, the menuconfig for the LinkIt smart u-boot repo did not have the option to do those things. I’m not too comfortable with the u-boot and builroot code, so I was hoping for some help with how I may be able to add those options into the LinkIt smart u-boot, or add support for my LinkIt board to a clone of the main u-boot repo.

My main fear is putting a bad/wrong u-boot onto the board and bricking it.

Thanks for any advice!