BuildRoot for Raspberry Pi

This buildroot fork will produce a very light-weight and trimmed down toolchain, rootfs and kernel for the Raspberry Pi. It's intended for advanced users and specific embedded applications.

The default configuration is trimmed down but still contains a few applications to help with development and testing, it should be trimmed down further and secured before actual field deployment.

Test Drive

You can test drive rpi-buildroot by following the instructions below:

wget http://dl.guillermoamaral.com/rpi/sdcard.img.xz
xz -d sdcard.img.xz
sudo dd if=sdcard.img of=/dev/sdx # replace *sdx* with your actual sdcard device node

The default user is root, no password will be requested.

Toolchain

I've added a toolchain, it has everything needed to cross-compile software for use with the test-drive image, download and usage instructions below:

wget http://dl.guillermoamaral.com/rpi/rpi-buildroot-toolchain.tar.xz
tar -xvJf rpi-buildroot-toolchain.tar.xz
source rpi-buildroot-toolchain/env
$CC -I"${BUILDROOT_HOST_DIR}/usr/include" \
    -I"${BUILDROOT_STAGING_DIR}/usr/include" \
    -I"${BUILDROOT_STAGING_DIR}/opt/vc/include" \
    -L"${BUILDROOT_STAGING_DIR}/opt/vc/lib" \
    -L"${BUILDROOT_STAGING_DIR}/usr/lib" \
    -L"${BUILDROOT_STAGING_DIR}/lib" \
    -L"${BUILDROOT_TARGET_DIR}/opt/vc/lib" \
    -L"${BUILDROOT_TARGET_DIR}/usr/lib" \
    -L"${BUILDROOT_TARGET_DIR}/lib" \
    main.c # example usage

If you're interested in using the toolchain with CMake, you may want to download the toolchain cmake file used with Marshmallow Game Engine:

wget https://github.com/gamaral/marshmallow_h/blob/master/cmake/Toolchain-buildroot.cmake
# The **env** file needs to be **sourced** before executing the following command
cmake -DCMAKE_TOOLCHAIN_FILE=Toolchain-buildroot.cmake .
make

Building

git clone --depth 1 git://github.com/gamaral/rpi-buildroot.git
cd rpi-buildroot
make raspberrypi_defconfig
make nconfig         # if you want to add packages or fiddle around with it
make                 # build (NOTICE: Don't use the **-j** switch, it's set to auto-detect)

Updating

Since I keep this overlay fork rebased to buildroot master, you will need to replace your local branch completely:

git fetch origin
git checkout origin/rpi
git checkout -B rpi

I added a little helper script to the base directory that can do the legwork:

./rpi-buildroot-update.sh

Deploying

You will need to create two partitions in your sdcard, the first (boot) needs to be a small W95 FAT32 (LBA) patition (that's partition id c), about 50 MB will do.

Notice you will need to replace sdx in the following commands with the actual device node for your sdcard.

# run the following as root
mkfs.vfat -F 32 -n boot /dev/sdx1
mkdir -p /media/boot
mount /dev/sdx1 /media/boot

You will need to copy all the files in output/target/boot to your boot partition.

# run the following as root
cp output/target/boot/* /media/boot
umount /media/boot

The second (rootfs) can be as big as you want, but with a 200 MB minimum, and formated as ext4.

# run the following as root
mkfs.ext4 -L rootfs /dev/sdx2
mkdir -p /media/rootfs
mount /dev/sdx2 /media/rootfs

You will need to extract output/images/rootfs.tar onto the partition, as root.

# run the following as root
tar -xvpsf output/images/rootfs.tar -C /media/rootfs # replace with your mount directory
umount /media/rootfs