From eLinux.org
< R-Car
Revision as of 08:45, 7 December 2017 by Marex (talk | contribs)
Jump to: navigation, search


This is the Wiki for the U-Boot on Renesas R-Car Gen3 SoCs and boards . Refer to the R-Car page for information about Renesas' R-Car SoC family.

Supported boards

As of U-Boot 2018.01-rc1, the following boards are supported:

Supported boards in U-Boot 2018.01-rc1
Board U-Boot defconfig Update procedure
R8A7795 H3 ULCB r8a7795_ulcb_defconfig Flashing firmware
R8A7796 M3 ULCB r8a7796_ulcb_defconfig Flashing firmware
R8A7795 H3 Salvator-X ES2.0+ r8a7795_salvator-x_defconfig N/A
R8A7796 M3 Salvator-X r8a7796_salvator-x_defconfig N/A

! WARNING: R-Car R8A7795 H3 ES1.x is NOT supported!

Building U-Boot manually

Building U-Boot can be done manually by using the U-Boot sources. This process does NOT produce IPL/ATF/BL binaries, only U-Boot binary is produced.


  • Running mainline U-Boot is only supported with IPL/ATF/BL revision 2.23 and newer.
  • ARM cross-compiler is mandatory to build U-Boot.

ARM cross-compiler

If you intend to build both IPL/ATF/BL and U-Boot using OpenEmbedded with meta-renesas layer, you can skip this step.

Debian and Ubuntu includes an ARM cross-compiler in its standard package feed. You can install it as follows:

apt-get install gcc-aarch64-linux-gnu

Other distributions likely also provide ARM cross-compilers. Consult distro-specific documentation for details.

Obtain U-Boot sources

The preferred method of obtaining U-Boot sources is through git VCS, using git protocol:

git clone git://git.denx.de/u-boot.git

or via HTTP:

git clone http://git.denx.de/u-boot.git

Finally, check out the version of U-Boot that will be used for the build:

cd u-boot
git checkout -b my_working_branch v2018.01-rc1

U-Boot git hosting also provides snapshots.

Prepare build environment

Before building U-Boot for R-Car Gen3 system, the following environment variables need to be configured:

export ARCH=arm64
export CROSS_COMPILE=aarch64-linux-gnu-

The later variable must match the prefix of the Aarch64 cross-toolchain installed on your system, the example above is valid for Debian and Ubuntu,

Build U-Boot

To produce u-boot-elf.srec file during U-Boot build, a patch [1] must first be applied:

git am 0001-Makefile-add-u-boot-elf.srec-if-CONFIG_REMAKE_ELF-is.patch

or in case U-Boot snapshot was used:

patch -Np1 -i 0001-Makefile-add-u-boot-elf.srec-if-CONFIG_REMAKE_ELF-is.patch

The U-Boot sources must be configured for a particular supported platform. List of supported platforms and matching U-Boot defconfigs is available at supported boards.

make r8a779x_y_defconfig

for example to configure U-Boot sources for R8A7795 H3 ULCB board:


Once configured, U-Boot sources can be compiled to produce u-boot.bin and optionally u-boot-elf.srec:


To speed up build process, -jN option can be passed to make to start multiple jobs at the same time, this is beneficial especially on SMP systems. The following example starts up to (number of CPUs in a system + 1) jobs, which is the recommended amount:

make -j`expr \`nproc\` + 1`

Building IPL/ATF/BL and U-Boot using OpenEmbedded

Building all the components of the boot process can also be done using OpenEmbedded . By adding two extra patches on top of meta-renesas layer, it is possible to build mainline U-Boot alongside all the other components. The two patches add U-Boot 2018.01-rc1 recipe and switch preferred version of U-Boot to 2018.01% and are available from [2] [3] and the patched meta-renesas layer is available at [4] .

To build IPL/ATF/BL/U-Boot using OpenEmbedded, follow the standard build procedure, but use the patched meta-renesas layer.

Flashing U-Boot

Each platform has a slightly different process for updating the content of the flash. The list of supported boards contains links to instructions for updating each supported board.