1Here is the step-by-step to boot to U-Boot on RK3368-uQ7
2
3Get the Source and build ATF
4============================
5
6  > git clone git://git.theobroma-systems.com/arm-trusted-firmware.git
7  > cd arm-trusted-firmware
8  > make CROSS_COMPILE=aarch64-linux-gnu- PLAT=rk3368 bl31
9  > cp build/rk3368/release/bl31.bin ../u-boot/bl31-rk3368.bin
10
11Configure U-Boot
12================
13
14  > cd ../u-boot
15  > make lion-rk3368_defconfig
16
17Build the TPL/SPL stage
18=======================
19
20  > make CROSS_COMPILE=aarch64-unknown-elf- ARCH=arm
21  > tools/mkimage -n rk3368 -T rksd -d tpl/u-boot-tpl.bin spl-3368.img
22  > cat spl/u-boot-spl-dtb.bin >> spl-3368.img
23
24Build the full U-Boot and a FIT image including the ATF
25=======================================================
26
27  > make CROSS_COMPILE=aarch64-unknown-elf- ARCH=arm u-boot.itb
28
29Flash the image
30===============
31
32Copy the SPL to offset 32k and the FIT image containing the payloads
33(U-Boot proper, ATF, devicetree) to offset 256k card.
34
35SD-Card
36-------
37
38  > dd if=spl-3368.img of=/dev/sdb seek=64
39  > dd if=u-boot.itb of=/dev/sdb seek=512
40
41eMMC
42----
43
44rkdeveloptool allows to flash the on-board eMMC via the USB OTG interface with
45help of the Rockchip loader binary.
46
47  > git clone https://github.com/rockchip-linux/rkdeveloptool
48  > cd rkdeveloptool
49  > autoreconf -i && && ./configure && make
50  > git clone https://github.com/rockchip-linux/rkbin.git
51  > ./rkdeveloptool db rkbin/rk33/rk3368_loader_v2.00.256.bin
52  > ./rkdeveloptool wl 64 ../spl.img
53  > ./rkdeveloptool wl 512 ../u-boot.itb
54
55
56If everything went according to plan, you should see the following
57output on UART0:
58
59<debug_uart> U-Boot TPL board init
60Trying to boot from BOOTROM
61Returning to boot ROM...
62Trying to boot from MMC1
63NOTICE:  BL31: v1.3(release):v1.2-1320-gbf43a443
64NOTICE:  BL31: Built : 18:04:47, Jul  5 2017
65
66
67U-Boot 2017.07-00158-g2395e99858 (Jul 18 2017 - 21:03:31 +0200)
68
69Model: Theobroma Systems RK3368-uQ7 SoM
70DRAM:  2 GiB
71MMC:   dwmmc@ff0c0000: 1, dwmmc@ff0f0000: 0
72Using default environment
73
74In:    serial@ff180000
75Out:   serial@ff180000
76Err:   serial@ff180000
77Net:
78Warning: ethernet@ff290000 (eth0) using random MAC address - d2:69:35:7e:d0:1e
79eth0: ethernet@ff290000
80Hit any key to stop autoboot:  2
81