U-Boot 2015.04.y
From IGEP - ISEE Wiki
Build u-boot from sources
Download from ISEE GIT Repository
git clone git://git.isee.biz/pub/scm/u-boot-fslc.git cd u-boot-fslc/ git checkout remotes/origin/isee-imx-patches-2015.04-next -b isee-imx-patches-2015.04-next.local
Also, it could download from GIT Repositories (http://git.isee.biz/) and test the last unstable version at your own risk (see "U-Boot Mainline Series" chapter in The bootloader U-Boot)
Configure U-Boot for IGEP SMARC iMX6 device.(select quad -> imx6q or dual lite -> imx6dl or solo -> imx6s)
make CROSS_COMPILE=[your cross compiler] mx6q_igep0046_defconfig or make CROSS_COMPILE=[your cross compiler] mx6dl_igep0046_defconfig or make CROSS_COMPILE=[your cross compiler] mx6s_igep0046_defconfig
Then build the SPL and the u-boot image. The result will be an MLO file and an u-boot.img file in current directory. Execute:
make CROSS_COMPILE=[your cross compiler]