OpenWrt build system is the buildsystem for the OpenWrt Linux distribution. OpenWrt build system works on GNU/Linux, BSD or MacOSX operating system. A case-sensitive filesystem is required.

It is recommended that you use a GNU/Linux distribution (Debian), either a standalone installation or one running in a virtual environment (VMware or Qemu).

Ubuntu under Windows Subsystem for Linux is not an officially supported environment, but it appears to produce good builds. Cygwin(Windows) will not be supported because of the lack of case sensitivity in the file system.

Outdated information for old Buildroot versions, old GNU/Linux variants is archived at: buildroot.exigence.old

For common problems, benchmarks, common optimizations see development

To generate an installable OpenWrt firmware image file with a size of e.g. 8MB, you need:

• ca. 200 MB of hard disk space for OpenWrt build system
• ca. 300 MB of hard disk space for OpenWrt build system + OpenWrt Feeds
• ca. 2.1 GB of hard disk space for source packages downloaded during build from OpenWrt Feeds
• ca. 3-4 GB of available hard disk space to build (i.e. cross-compile) OpenWrt and generate the firmware file

• ca. 1-4 GB of RAM to build Openwrt.(build x86's img need 4GB RAM)

1. Do everything as non-root user! 2. Issue all OpenWrt build system commands in the <buildsystem root> directory, e.g. ~/openwrt/trunk/ 3. Do not build in a directory that has spaces in its full path 4. Change ownership of the directory where you downloaded the OpenWrt to other than root user (sudo chown -R user:user /openwrt/)

git.openwrt.org contains outdated source code. Only https://github.com/openwrt/openwrt.git has the current source for Openwrt trunk and Chaos Calmer branch

1. Install git , to conveniently download the OpenWrt source code, and build tools to do the cross-compilation process:

   sudo apt-get update
   sudo apt-get install git-core build-essential libssl-dev libncurses5-dev unzip gawk zlib1g-dev

   Some feeds might not available over git but only via subversion (short: svn) or mercurial. If you want to obtain their source-code, you need to install svn and mercurial as well:

   sudo apt-get install subversion mercurial

   • for information about the build tools see make and build-essential
   • for information about git see git(7)
   • for information about the subversion tool see svn and subversion documentation (multiple languages)
2. Download the OpenWrt bleeding edge (trunk version) with git (see Downloading Sources for more options!):

   git clone https://github.com/openwrt/openwrt.git

   this creates a directory 'openwrt', which is the OpenWrt build system build-directory
   the OpenWrt toolchain "OpenWrt build system" is included
   alternatively use HTTPS to download zipped sources.
   filename: openwrt-master.zip
   current checksums:
   md5: e450f968e19abd733458a1b3b2fe59c8
   sha256: 4f268c75c5525c5a9a74766a2e473aa085ed7a1262fda72c0e9575b48414fdba
   

1. (optional) Download and install all available "feeds" (see OpenWrt Feeds for more options!):

   cd openwrt
   ./scripts/feeds update -a
   ./scripts/feeds install -a

2. Make OpenWrt build system check for missing packages on your build-system using ONE of the following commands:

   make menuconfig (most likely you would like to use this)
   -OR-
   make defconfig
   -OR-
   make prereq
   //Note: If you use these in order, or use more than one, the **compilation will fail**.//

   There you will need to select what you want to compile.
3. Proceed with build (i.e. cross-compile the downloaded sources to binaries)\\After the cross-compilation process the trunk-directory contained over 240000 files with a total size of above 3GiB!

Here's a table with the package name for each prerequisite separated for different GNU/Linux and Unix like distributions.

Unfortunately not all dependencies are checked by make config:

• Arch Linux

  pacman -S --needed subversion asciidoc bash bc binutils bzip2 fastjar flex git gcc util-linux gawk intltool zlib mercurial make cdrkit ncurses openssl patch perl-extutils-makemaker rsync sdcc unzip wget gettext libxslt boost libusb bin86 sharutils b43-fwcutter findutils

• Debian 7 Wheezy:

  apt-get install libncurses5-dev zlib1g-dev gawk

• Debian 8 Jessie:

  sudo apt-get install build-essential libncurses5-dev gawk git subversion libssl-dev gettext unzip zlib1g-dev file python

• Fedora 24 - 64Bit :

  dnf install -y subversion binutils bzip2 gcc gcc-c++ gawk gettext git-core flex ncurses-devel ncurses-compat-libs zlib-devel zlib-static make patch unzip perl-ExtUtils-MakeMaker perl-Thread-Queue \
   glibc glibc-devel glibc-static quilt sed sdcc intltool sharutils bison wget openssl-devel

• openSUSE

  zypper install --no-recommmends asciidoc bash bc binutils bzip2 fastjar flex gawk gcc gcc-c++ git-core util-linux  gtk2-devel intltool jikes zlib-devel zlib-devel-static mercurial make genisoimage ncurses-devel libopenssl-devel patch perl-ExtUtils-MakeMaker python-devel rsync ruby sdcc unzip wget gettext-tools libxslt-tools subversion

• Ubuntu 12.04LTS:

  sudo apt-get install build-essential subversion git-core libncurses5-dev zlib1g-dev gawk flex quilt libssl-dev xsltproc libxml-parser-perl mercurial bzr ecj cvs unzip

• Ubuntu 64bit:

  sudo apt-get install build-essential subversion libncurses5-dev zlib1g-dev gawk gcc-multilib flex git-core gettext libssl-dev unzip

• Centos x86-64 (some packages require EPEL):

  yum install subversion binutils bzip2 gcc gcc-c++ gawk gettext flex ncurses-devel zlib-devel zlib-static make patch unzip perl-ExtUtils-MakeMaker glibc glibc-devel glibc-static quilt ncurses-libs sed sdcc intltool sharutils bison wget git-core openssl-devel xz

• Gentoo:

  $ echo \
      app-arch/{bzip2,fastjar,sharutils,unzip,zip} \
      app-text/asciidoc dev-java/{icedtea:7,jikes,oracle-jdk-bin} \
      dev-libs/{libusb-compat,libxslt,openssl} dev-util/intltool \
      dev-vcs/{git,mercurial} net-misc/{rsync,wget} \
      net-wireless/b43-fwcutter sys-apps/{gawk,util-linux} \
      sys-devel/{bc,bin86,binutils,dev86,flex,gcc[gcj],gettext} \
      sys-libs/{ncurses,zlib} virtual/{cdrtools,perl-ExtUtils-MakeMaker} \
      x11-libs/gtk+:2 \
          | sed 's/\s/\n/g' \
              | sort \
                  | sudo tee /etc/portage/sets/openwrt-prerequisites \
                      && sudo emerge -DuvNa '@openwrt-prerequisites'

• alpine linux uses musl as libc replacement. On alpine 3.6, some programs to compile (ex: u-boot). A list of packages to install: apk add git asciidoc bash bc binutils bzip2 flex gcc g++ gawk make wget perl file ncurses-dev tar findutils coreutils unzip grep zlib-dev patch linux-headers diffutils

cloning the Git repository using one of the following commands. Note that the main source repos have all been moved to Github in 2016.

The development branch (master) contains everything from documentation to experimental patches.

git clone git://github.com/openwrt/openwrt.git

Additional packages can be found in several feeds (Luci, packages, routing, management etc.). Let the Openwrt build system to clone the correct feeds into feeds/packages, feeds/luci etc.

git clone -b chaos_calmer git://github.com/openwrt/chaos_calmer.git

Additional packages can be found in several feeds (Luci, packages, routing, management etc.). Let the Openwrt build system to clone the correct feeds into feeds/packages, feeds/luci etc.

git clone -b barrier_breaker git://github.com/openwrt/archive.git

Additional packages can be found in several feeds (Luci, packages, routing, management etc.). Let the Openwrt build system to clone the correct feeds into feeds/packages, feeds/luci etc.

git clone -b attitude_adjustment git://github.com/openwrt/archive.git

git clone git://git.openwrt.org/12.09/packages.git

Note: The location of the Luci feed has not been corrected in feeds.conf.default after the move to Github, so you need to manually edit feeds.conf.default to pull Luci from Github:

src-git luci https://github.com/openwrt/luci.git;luci-0.11

git clone git://git.openwrt.org/10.03/openwrt.git backfire

git clone git://git.openwrt.org/10.03/packages.git