Setup Build Environment
sudo apt-get update
sudo apt-get install git-core subversion mercurial build-essential libssl-dev libncurses5-dev unzip gawk zlib1g-dev
Fetch the source tree from Openwrt git repo
git clone https://github.com/openwrt/openwrt.git
cd openwrt
./scripts/feeds update -a
./scripts/feeds install -a
make menuconfig