Here is the step-by-step to boot to U-Boot on RK3368-uQ7 Get the Source and build ATF ============================ > git clone git://git.theobroma-systems.com/arm-trusted-firmware.git > cd arm-trusted-firmware > make CROSS_COMPILE=aarch64-linux-gnu- PLAT=rk3368 bl31 > cp build/rk3368/release/bl31.bin ../u-boot/bl31-rk3368.bin Configure U-Boot ================ > cd ../u-boot > make lion-rk3368_defconfig Build the TPL/SPL stage ======================= > make CROSS_COMPILE=aarch64-unknown-elf- ARCH=arm > tools/mkimage -n rk3368 -T rksd -d tpl/u-boot-tpl.bin spl-3368.img > cat spl/u-boot-spl-dtb.bin >> spl-3368.img Build the full U-Boot and a FIT image including the ATF ======================================================= > make CROSS_COMPILE=aarch64-unknown-elf- ARCH=arm u-boot.itb Flash the image =============== Copy the SPL to offset 32k and the FIT image containing the payloads (U-Boot proper, ATF, devicetree) to offset 256k card. SD-Card ------- > dd if=spl-3368.img of=/dev/sdb seek=64 > dd if=u-boot.itb of=/dev/sdb seek=512 eMMC ---- rkdeveloptool allows to flash the on-board eMMC via the USB OTG interface with help of the Rockchip loader binary. > git clone https://github.com/rockchip-linux/rkdeveloptool > cd rkdeveloptool > autoreconf -i && && ./configure && make > git clone https://github.com/rockchip-linux/rkbin.git > ./rkdeveloptool db rkbin/rk33/rk3368_loader_v2.00.256.bin > ./rkdeveloptool wl 64 ../spl.img > ./rkdeveloptool wl 512 ../u-boot.itb If everything went according to plan, you should see the following output on UART0: U-Boot TPL board init Trying to boot from BOOTROM Returning to boot ROM... Trying to boot from MMC1 NOTICE: BL31: v1.3(release):v1.2-1320-gbf43a443 NOTICE: BL31: Built : 18:04:47, Jul 5 2017 U-Boot 2017.07-00158-g2395e99858 (Jul 18 2017 - 21:03:31 +0200) Model: Theobroma Systems RK3368-uQ7 SoM DRAM: 2 GiB MMC: dwmmc@ff0c0000: 1, dwmmc@ff0f0000: 0 Using default environment In: serial@ff180000 Out: serial@ff180000 Err: serial@ff180000 Net: Warning: ethernet@ff290000 (eth0) using random MAC address - d2:69:35:7e:d0:1e eth0: ethernet@ff290000 Hit any key to stop autoboot: 2