U-Boot for LibreTech CC ‘LePotato’ (S905X)

LibreTech CC is a Single Board Computer manufactured by Libre Computer Technology with the following specifications:

v1:

  • Amlogic S905X ARM Cortex-A53 quad-core SoC @ 1.5GHz

  • ARM Mali 450 GPU

  • 2GB DDR3 SDRAM

  • 10/100 Ethernet

  • HDMI 2.0 4K/60Hz display

  • 40-pin GPIO header

  • 4 x USB 2.0 Host

  • eMMC, microSD

  • Infrared receiver

  • Jack for CVBS and Audio

v2:

  • Added SPI NOR

  • Removed Jack

Schematics are available on the manufacturer website.

U-Boot Compilation

$ export CROSS_COMPILE=aarch64-none-elf-
$ make libretech-cc_defconfig
$ make

Use libretech-cc_v2_defconfig for v2.

U-Boot Signing with Pre-Built FIP repo

$ git clone https://github.com/LibreELEC/amlogic-boot-fip --depth=1
$ cd amlogic-boot-fip
$ mkdir my-output-dir
$ ./build-fip.sh lepotato /path/to/u-boot/u-boot.bin my-output-dir

U-Boot Manual Signing

Amlogic does not provide sources for the firmware and tools needed to create a bootloader image so it is necessary to obtain binaries from sources published by the board vendor:

$ wget https://releases.linaro.org/archive/13.11/components/toolchain/binaries/gcc-linaro-aarch64-none-elf-4.8-2013.11_linux.tar.xz
$ wget https://releases.linaro.org/archive/13.11/components/toolchain/binaries/gcc-linaro-arm-none-eabi-4.8-2013.11_linux.tar.xz
$ tar xvfJ gcc-linaro-aarch64-none-elf-4.8-2013.11_linux.tar.xz
$ tar xvfJ gcc-linaro-arm-none-eabi-4.8-2013.11_linux.tar.xz
$ export PATH=$PWD/gcc-linaro-aarch64-none-elf-4.8-2013.11_linux/bin:$PWD/gcc-linaro-arm-none-eabi-4.8-2013.11_linux/bin:$PATH
$ git clone https://github.com/BayLibre/u-boot.git -b libretech-cc amlogic-u-boot
$ cd amlogic-u-boot
$ make libretech_cc_defconfig
$ make
$ export FIPDIR=$PWD/fip

Go back to the mainline U-Boot source tree then:

$ mkdir fip

$ cp $FIPDIR/gxl/bl2.bin fip/
$ cp $FIPDIR/gxl/acs.bin fip/
$ cp $FIPDIR/gxl/bl21.bin fip/
$ cp $FIPDIR/gxl/bl30.bin fip/
$ cp $FIPDIR/gxl/bl301.bin fip/
$ cp $FIPDIR/gxl/bl31.img fip/
$ cp u-boot.bin fip/bl33.bin

$ $FIPDIR/blx_fix.sh \
          fip/bl30.bin \
          fip/zero_tmp \
          fip/bl30_zero.bin \
          fip/bl301.bin \
          fip/bl301_zero.bin \
          fip/bl30_new.bin \
          bl30

$ $FIPDIR/acs_tool.pyc fip/bl2.bin fip/bl2_acs.bin fip/acs.bin 0

$ $FIPDIR/blx_fix.sh \
          fip/bl2_acs.bin \
          fip/zero_tmp \
          fip/bl2_zero.bin \
          fip/bl21.bin \
          fip/bl21_zero.bin \
          fip/bl2_new.bin \
          bl2

$ $FIPDIR/gxl/aml_encrypt_gxl --bl3enc --input fip/bl30_new.bin
$ $FIPDIR/gxl/aml_encrypt_gxl --bl3enc --input fip/bl31.img
$ $FIPDIR/gxl/aml_encrypt_gxl --bl3enc --input fip/bl33.bin
$ $FIPDIR/gxl/aml_encrypt_gxl --bl2sig --input fip/bl2_new.bin --output fip/bl2.n.bin.sig
$ $FIPDIR/gxl/aml_encrypt_gxl --bootmk \
                              --output fip/u-boot.bin \
                              --bl2 fip/bl2.n.bin.sig \
                              --bl30 fip/bl30_new.bin.enc \
                              --bl31 fip/bl31.img.enc \
                              --bl33 fip/bl33.bin.enc

Then write U-Boot to SD or eMMC with:

$ DEV=/dev/boot_device
$ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=512 skip=1 seek=1
$ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=1 count=440