This repository already build from the source code
The firmware with the kernel 3.4.x
You can build it from the source code by yourself:
Install all the required packages first
sudo apt-get install autoconf automake bison build-essential flex gawk gettext gperf libtool pkg-config zlib1g-dev libgmp3-dev libmpc-dev libmpfr-dev texinfo python-docutils mc
Starting bulid
git clone clone https://bitbucket.org/padavan/rt-n56u.git
cd ./rt-n56u/toolchain-mipsel
sudo ./clean_sources
If you plan to build the firmware with the kernel 3.4.x
sudo ./build_toolchain
If you plan to build the firmware with the kernel 3.0
sudo ./build_toolchain_3.0.x