PANiCnz If using the official nightlies you can either use the "box" image with the correct dtb named in uEnv.ini written to USB - this uses the internal SPI u-boot which will find our boot files, or you can use the "lafrite" image which uses extlinux boot config and our own u-boot. The C2/K2 extlinux images will not boot on LaFrite; the C2/K2 are GXBB devices and LaFrite is GXL, so the device-specific u-boot 'fip' sources are not compatible. Note that the 512MB LaFrite board will boot but Kodi will not start due to the current CMA allocation in device-tree/kernel. If you search the forums there's a thread where another 512MB board user figured out some tweaked settings that allow Kodi to run - and he is sharing his images.
erbas If you want to boot a Ki-Pro you need to use the 'box' image. The C2 u-boot BL1 firmware checks for C2 hardware and aborts if not found. We do not (and have no plan to) support emmc install on GXBB hardware.