The environment for U-Boot 2017.05-rc1 has: fdtfile=amlogic/meson-gxbb-odroidc2.dtb
The relevant setting in U-Boot is in file include/configs/odroid-c2.h #define MESON_FDTFILE_SETTING \ "fdtfile=amlogic/meson-gxbb-odroidc2.dtb\0"
The environment for U-Boot 2017.05-rc1 has: fdtfile=amlogic/meson-gxbb-odroidc2.dtb
The relevant setting in U-Boot is in file include/configs/odroid-c2.h #define MESON_FDTFILE_SETTING \ "fdtfile=amlogic/meson-gxbb-odroidc2.dtb\0"