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.
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If you're not familiar with Buildroot and what it can and can't do, please take the time to read the manual.
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You must be pretty comfortable with cross-compilation in order to use rpi-buildroot.
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.
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_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
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)
I've added a script that can automatically flash your sdcard, you simply need to point it to the correct device node, confirm and you're done!
Notice you will need to replace sdx in the following commands with the actual device node for your sdcard.
# run the following as root (sudo)
board/raspberrypi/mksdcard /dev/sdx
You will need to create two partitions in your sdcard, the first (boot) needs to be a small W95 FAT16 (LBA) patition (that's partition id e), about 32 MB will do.
Notice you will need to replace sdx in the following commands with the actual device node for your sdcard.
Create the partitions on the SD card. Run the following as root. Notice all data on the SD card will be lost.
fdisk /dev/sdx
> p # prints partition table
> d # repeat until all partitions are deleted
> n # create a new partition
> p # create primary
> 1 # make it the first partition
> <enter> # use the default sector
> +32M # create a boot partition with 32MB of space
> n # create rootfs partition
> p
> 2
> <enter>
> <enter> # fill the remaining disk, adjust size to fit your needs
> p # double check everything looks right
> w # write partition table to disk.
Now format the boot partition as FAT 16
# run the following as root
mkfs.vfat -F16 -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