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