Manual Build

At least on Ubuntu 14.10, it is possible to use the prepackaged `gcc-arm-linux-gnueabihf` toolchain to build uboot, linux, and busybox to prepare a very small working image with minimal source customization.

apt-get install gcc-arm-linux-gnueabihf
wget https://www.kernel.org/pub/linux/kernel/v3.x/linux-3.18.tar.xz
wget https://github.com/inversepath/u-boot-usbarmory/archive/usbarmory.zip
wget http://busybox.net/downloads/busybox-1.22.1.tar.bz2

unzip usbarmory.zip
tar xf linux-3.18.tar.xz
tar xf busybox-1.22.1.tar.bz2

cd u-boot-usbarmory-usbarmory
env ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- make usbarmory_config all

cd linux-3.18
cp ~/usbarmory-github/kernel-config .config
cp ~/usbarmory-github/imx53-usbarmory.dts arch/arm/boot/dts/
# edit arch/arm/boot/dts/Makefile to add "imx53-usbarmory.dtb" in with the other imx53 devices
env ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- make menuconfig # any local changes...
env ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- make -j4 uImage LOADADDR=0x70008000 dtbs modules
mkdir -p /tmp/linux-3.18/{boot,lib}
cp arch/arm/boot/{uImage,dts/imx53-usbarmory.dtb} /tmp/linux-3.18/boot
env ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- make modules_install INSTALL_MOD_PATH=/tmp/linux-3.18