Using u-boot on Creator (Ci40) Marduk platform
Toolchain setup
If you are using the toolchain produced by OpenWrt you must setup the environment as explained here.
For the MIPS official toolchain see here.
Configure and build it
$ make CROSS_COMPILE=<toolchain-prefix> pistachio_marduk_defconfig
$ make CROSS_COMPILE=<toolchain-prefix>
This will generate u-boot-pistachio_<board_name>-<version>.img
eg. u-boot-pistachio_marduk-2015.10-v1.0.4.img
OR u-boot-pistachio_<board_name>-<version>-<githash>.img, if there are extra commits above the tag.
e.g. u-boot-pistachio_marduk-2015.10-v1.0.4-g75cbe38.img
Flash it onto your Ci40
See our docs.