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The toolchain is a set of binaries, system libraries and tools which allow you to build (in our case, cross-compile) u-boot and the kernel for a target platform. This will, to some limited extent, need to match the target rootfs. A large and incompatible change has taken place recently, through the Hard Float ABI. Now, two different debian and ubuntu ports are binary incompatible with each other.


Part of distributions


Recent (from 12.04 on)

A complete cross toolchain is available as a package, just run:

apt-get install gcc-arm-linux-gnueabihf


For older versions, you need to use an external repository.

add-apt-repository ppa:linaro-maintainers/toolchain
apt-get update
apt-get install gcc-arm-linux-gnueabihf


Details on Cross-development Toolchains for Debian are at the Debian Wiki.
Note: Debian now has cross-toolchains in the archive, superseding those at

Currently (December 2015) available for unstable and testing in the standard repositories.

Install Cross Compiler and build utilities:

dpkg --add-architecture armhf
apt-get update
apt-get install g++-arm-linux-gnueabihf

You might want additional tools for building a sunxi system that are not related to the cross-compiler:

apt-get install build-essential git debootstrap u-boot-tools device-tree-compiler


A complete cross toolchain is available as a package, just run:

yum install gcc-arm-linux-gnu


The crossdev tool[1] is the standard way of dealing with crosscompilers in Gentoo. Command line options are used to specify any arbitrary mix of different versions of the kernel headers, glibc, binutils and gcc. You can also use the -S option instead (to pick whatever is considered to be stable at the moment), but in this case the crosscompiler will be also upgraded as part of the regular distribution updates, which might be a bit annoying.

ARM crosscompiler

Even though Gentoo normally uses armv7a-hardfloat-linux-gnueabi as the toolchain triplet on ARM, we can also use Debian alike arm-linux-gnueabihf variant in order to be able to use the compilation instructions from the linux-sunxi wiki as-is (without substituting the toolchain name).

emerge crossdev
crossdev --kernel =3.18 --libc =2.20-r2 --binutils =2.24-r3 --gcc =4.8.5 \
         --genv 'USE="-fortran -mudflap -nls -openmp multilib" EXTRA_ECONF="--with-cpu=cortex-a8 --with-float=hard"' -t arm-linux-gnueabihf

ARM64 crosscompiler

emerge crossdev
crossdev --kernel =3.18 --libc =2.21-r1 --binutils =9999 --gcc =4.9.3 \
         --genv 'USE="-fortran -mudflap -nls -openmp multilib -sanitize" EXTRA_ECONF="--enable-fix-cortex-a53-843419"' -t aarch64-linux-gnu

Note: binutils =9999 (fetch sources from git) should be replaced with =2.26 as soon as binutils 2.26 is added to portage. Such new binutils version is necessary for having a Cortex-A53 erratum 843419 workaround.

OpenRISC crosscompiler

If you have one of the Allwinner SoC variants with an additional OpenRISC core (for example A31 and H3 have it), then you might want to also build an OpenRISC crosscompiler too:

emerge crossdev
mkdir -p /etc/portage/patches/cross-or1k-elf/gcc-5.2.0
cd /etc/portage/patches/cross-or1k-elf/gcc-5.2.0
crossdev --binutils =2.25.1-r1 --gcc =5.2.0 --libc = \
         --genv 'USE="cxx multilib -fortran -mudflap -nls -openmp -sanitize"' \
         -s4 -t or1k-elf

Please note that the upstream GCC does not support OpenRISC yet, so the OpenRISC code is still brewing in and we can solve this problem by just providing a patch for GCC in the /etc/portage/patches directory.

  1. The Gentoo website has undergone a major overhaul as of April 2015. While a backup of the old content is still available, it seems to have left the Gentoo Embedded Handbook in a non-functional state. You can still find a copy via The wiki article on Raspberry Pi Cross building might also be helpful.


These standalone toolchains are big tarballs which come with everything you need.

Linaro toolchain


Linaro has been very good at changing the location and availability of just about everything, making it very hard to keep a wiki up to date which refers to it. So the below download locations might be stale already.

Currently, the main selection page is here.

It lists the following toolchains:

When in doubt, try 4.7 first.

WARNING: Do not use the 4.8 gcc versions of the linaro toolchain to build legacy kernels (sunxi-3.4 etc.), those seem to have issues building the kernel. Use an earlier version instead. (TODO: Verify that this is still true today).


Take a gcc-linaro-<major>.<minor>-<year>.<month>.tar.xz file and untar it. You will find a bin directory in there. Temporarily add it to the environment you are building from:

export PATH="$PATH":/home/user/folder/gcc-linaro-arm-linux-gnueabihf-*_linux/bin/

no hardfloat?

Recent linaro toolchains are Hard Float (hf), this will be used throughout the wiki you see something like:

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-

Replace arm-linux-gnueabihf- with arm-linux-gnueabi- if your are not using a hardfloat toolchain.

Code Sourcery

Another option is to install the Sourcery toolchain from Code Sourcery (now in Mentor Graphics). Download Code Sourcery G++ 2010 9-50 (official link, email registration required)

Direct link: (unofficial link)

chmod +x arm-2010.09-50-arm-none-linux-gnueabi.bin

If you are using Ubuntu, you may need to switch to use bash shell (instead of dash shell)

sudo dpkg-reconfigure -plow dash      ( then choose [No], this changes from using dash shell to using bash shell )

It will now install CodeSourcery with a GUI installer

Follow default settings and do Next , Next, Next, etc…

It should install in: ~/CodeSourcery/ ( for example: /home/penguin/CodeSourcery/ )

Make sure the CodeSourcery binaries are added to your path (if your username is penguin, then this should be correct):

echo "export PATH=~/CodeSourcery/Sourcery_G++_Lite/bin:\${PATH}" >> ~/.bashrc
export PATH=~/CodeSourcery/Sourcery_G++_Lite/bin:$PATH   (or you can just spawn a new terminal window to update the path)
echo $PATH  (make sure your path is updated)

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