Here are the procedures and required packages for installing an OpenWRT build environment on Ubuntu.

Consult the OpenWRT Wiki first then issue the commands.


sudo apt-get install git openssl libssl-dev unzip build-essential binutils flex bison autoconf gettext texinfo sharutils subversion libncurses5-dev ncurses-term zlib1g-dev gawk python


git clone git://git.openwrt.org/15.05/openwrt.git

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

./scripts/feeds update -a

./scripts/feeds install -a

wget -O .config https://downloads.openwrt.org/chaos_calmer/15.05.1/ar71xx/generic/config.diff

make defconfig

make menuconfig

make prereq

and we have 2 ways to reduce the build time:

sed --in-place=.bak -e 's/=m$/=n/g' .config


to disable all optional modules in the beginning

or


make -j4 V=s IGNORE_ERRORS=m


to ignore all broken packages while building.