Buildroot fork for Embedded Linux course.
This repository contains support for building an Embedded Linux distribution (kernel, rootfilesystem) and a crosscompilation toolchain.
Install required tools:
sudo apt-get update
sudo apt-get install -y build-essential libncurses5-dev whois git subversion parted kpartx dosfstools extlinux qemu qemu-system putty
Clone this repository:
git clone --depth 1 https://github.com/fhict/el32-buildroot.git buildroot
Build an Embedded Linux distribution and crosscompilation toolchain for the Raspberri Pi.
For the Raspberry Pi B or B+ do as follows:
cd buildroot
make raspberrypi_defconfig
make source
make
In case you have a Raspberry PI 2 B you need to use a different defconfig:
cd buildroot
make raspberrypi2_defconfig
make source
make
If you have a Raspberry PI 3 B(+) use the following defconfig:
cd buildroot
make raspberrypi3_defconfig
make source
make
Now you will have to wait quite a while for the build to complete. If everything went well a kernel (zImage), a root filesystem (rootfs), and a bootable disk image (sdcard.img) will be available in the directory output/images.
The make source command is optional. It takes care that all required source code is downloaded from Internet and put in the dl directory. The make command will start the actual build process. It looks in the dl directory for required source code and only accesses the Internet when something is missing.
The toolchain generated by Buildroot is located by default in output/host. The simplest way to use it is to add output/host/usr/bin to your PATH environment variable (export PATH=$PATH:$HOME/buildroot/output/host/usr/bin). To make this permament enter it in your .bashrc file (echo 'export PATH=$PATH:$HOME/buildroot/output/host/usr/bin' >> ~/.bashrc). You can then use the crosscompilers simply as arm-linux-gcc (C compiler) and arm-linux-g++ (C++ compiler) without a path prefix.
The disk image should be written on a SD card and inserted in the Raspberry Pi. Writing the image on the SD card can be done as follows:
sudo umount /dev/sdc*
sudo dd if=output/images/sdcard.img of=/dev/sdc bs=4M
sudo sync
Above command assumes the SD card reader is connected as /dev/sdc. Check the output of the command dmesg | tail directly after inserting a SD card to see if this is the case. If not change the device name to comply with your configuration.
After booting the Raspberry Pi you should be able to login as root with password root.
Build an Embedded Linux distribution and crosscompilation toolchain for the Soekris NET4801 board:
cd buildroot
make soekris_net4801_defconfig
make source
make
Now you will have to wait quite a while for it to complete. If everything went well a kernel (bzImage), a root filesystem (rootfs), and a bootable disk image (soekris.img) will be available in the directory output/images.
The toolchain generated by Buildroot is located by default in output/host/. The simplest way to use it is to add output/host/usr/bin/ to your PATH environment variable (export PATH=$PATH:$HOME/buildroot/output/host/usr/bin). To make this permament enter it in your .bashrc file (echo 'export PATH=$PATH:$HOME/buildroot/output/host/usr/bin' >> ~/.bashrc). You can then use the crosscompilers simply as i586-linux-gcc (C compiler) and i586-linux-g++ (C++ compiler) without a path prefix.
The disk image should be written on a CompactFlash (CF) card and inserted in the Soekris board. Writing the image on the CF card can be done as follows:
sudo umount /dev/sdc*
sudo dd if=output/images/soekris.img of=/dev/sdc bs=1M
sudo sync
Above command assumes the CF card reader is connected as /dev/sdc. Check the output of the command dmesg | tail directly after inserting a CF card to see if this is the case. If not change the device name to comply with your configuration.
To test the kernel and rootfs with QEMU:
qemu-system-i386 -kernel output/images/bzImage -append "root=/dev/sda panic=1 console=ttyS0" -no-reboot -serial stdio -hda output/images/rootfs.ext2
This command will boot a virtualized Soekris. In fact it is running the Soekris root filesystem on a virtualized PC.
After booting the real or the virtual Soekris you should be able to login as root with password root.
This repository can be updated with newer versions of Buildroot as follows.
Clone this repository to your PC:
git clone https://github.com/fhict/el32-buildroot.git buildroot
cd buildroot
git checkout master
Check which branches are available at the official upstream Buildroot repository:
git remote show upstream
Choose a particular branch (e.g. master) and synchronize with it:
git pull -X theirs upstream master
Enter commit message or accept default one and save it.
Open raspberrypi3_defconfig in your favorite editor (e.g. gedit):
gedit configs/raspberrypi3_defconfig
Check if following customization lines are present, if not add them:
# Customization
BR2_ROOTFS_OVERLAY="board/raspberrypi/fs-overlay"
BR2_TARGET_GENERIC_HOSTNAME="raspberrypi"
BR2_TARGET_GENERIC_ISSUE="Welcome to Raspberry Pi!"
BR2_TARGET_GENERIC_ROOT_PASSWD="root"
BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y
BR2_PACKAGE_LIBUSB=y
BR2_PACKAGE_DROPBEAR=y
BR2_PACKAGE_IFPLUGD=y
Also check all the other raspberrypi*_defconfig files and modify them if necessary.
Commit changes
git commit -a -m "Customizations restored"
If you have cloned this repository on GitHub you could update your clone:
git push origin master