You will need install required packages before you start to build Linux kernel on your Ubuntu desktop.

$ sudo apt-get update
$ sudo apt-get install git
$ sudo apt-get install lib32stdc++6  lib32z1 lzop u-boot-tools
$ sudo apt-get install build-essential gcc
$ sudo apt-get install libncurses5-dev

This page introduce how you can download and compile the Linux kernel for ODROID-C1. You can select one of two version, GCC 4.9.2 or GCC 4.7.3. Since Linux release v1.1, the official toolchain for ODROID-C1 is switched to GCC 4.9.2.

Click one of the site to download toolchain to build Linux kernel.

• Download #1
• Download #2

Once the download is done, extract the tarball to /opt/toolchains/.

$ sudo mkdir -p /opt/toolchains
$ sudo tar xvf gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux.tar.xz -C /opt/toolchains/

In order to add the toolchain path to PATH, paste below lines to $HOME/.bashrc.

export ARCH=arm
export CROSS_COMPILE=arm-linux-gnueabihf-
export PATH=/opt/toolchains/gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux/bin/:$PATH

You can check if the toolchain installed above works properly while checking the version of toolchain. If you can find gcc version 4.9.2 20140904 (prerelease) at the end of the line, the toolchain is well installed.

$ arm-linux-gnueabihf-gcc -v
Using built-in specs.
COLLECT_GCC=/opt/toolchains/gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux/bin/arm-linux-gnueabihf-gcc
COLLECT_LTO_WRAPPER=/opt/toolchains/gcc-linaro-arm-linux-gnueabihf-4.9-2014.09_linux/bin/../libexec/gcc/arm-linux-gnueabihf/4.9.2/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: /cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/src/gcc-linaro-4.9-2014.09/configure --build=i686-build_pc-linux-gnu --host=i686-build_pc-linux-gnu --target=arm-linux-gnueabihf --prefix=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/install --with-sysroot=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/install/arm-linux-gnueabihf/libc --enable-languages=c,c++,fortran --disable-multilib --enable-multiarch --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=vfpv3-d16 --with-float=hard --with-pkgversion='crosstool-NG linaro-1.13.1-4.9-2014.09 - Linaro GCC 4.9-2014.09' --with-bugurl=https://bugs.launchpad.net/gcc-linaro --enable-__cxa_atexit --enable-libmudflap --enable-libgomp --enable-libssp --with-gmp=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-mpfr=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-mpc=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-isl=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-cloog=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-libelf=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --enable-threads=posix --disable-libstdcxx-pch --enable-linker-build-id --enable-plugin --enable-gold --with-local-prefix=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/install/arm-linux-gnueabihf/libc --enable-c99 --enable-long-long --with-mode=thumb --disable-multilib --with-float=hard
Thread model: posix
gcc version 4.9.2 20140904 (prerelease) (crosstool-NG linaro-1.13.1-4.9-2014.09 - Linaro GCC 4.9-2014.09) 

Click one of the site to download toolchain to build Linux kernel.

• Download #1
• Download #2

Once the download is done, extract the tarball to /opt/toolchains/.

$ sudo mkdir -p /opt/toolchains
$ sudo tar jxvf gcc-linaro-arm-linux-gnueabihf-4.7-2012.12-20121214_linux.tar.bz2 -C /opt/toolchains/

In order to add the toolchain path to PATH, paste below lines to $HOME/.bashrc.

export ARCH=arm
export CROSS_COMPILE=arm-linux-gnueabihf-
export PATH=/opt/toolchains/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux/bin:$PATH

You can apply the change if you login again or import to apply this change, login again or evaluate $HOME/.bashrc with source command.

$ source ~/.bashrc

You can check if the toolchain installed above works properly while checking the version of toolchain. If you can find gcc version 4.7.3 20130328 (prerelease) at the end of the line, the toolchain is well installed.

$ arm-linux-gnueabihf-gcc -v
Using built-in specs.
COLLECT_GCC=arm-linux-gnueabihf-gcc
COLLECT_LTO_WRAPPER=/opt/toolchains/gcc-linaro-arm-linux-gnueabihf-4.7-2013.04-20130415_linux/bin/../libexec/gcc/arm-linux-gnueabihf/4.7.3/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: /cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/src/gcc-linaro-4.7-2013.04/configure --build=i686-build_pc-linux-gnu --host=i686-build_pc-linux-gnu --target=arm-linux-gnueabihf --prefix=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/install --with-sysroot=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/install/arm-linux-gnueabihf/libc --enable-languages=c,c++,fortran --enable-multilib --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=vfpv3-d16 --with-float=hard --with-pkgversion='crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC 2013.04' --with-bugurl=https://bugs.launchpad.net/gcc-linaro --enable-__cxa_atexit --enable-libmudflap --enable-libgomp --enable-libssp --with-gmp=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-mpfr=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-mpc=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-ppl=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-cloog=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-libelf=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static --with-host-libstdcxx='-L/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/.build/arm-linux-gnueabihf/build/static/lib -lpwl' --enable-threads=posix --disable-libstdcxx-pch --enable-linker-build-id --enable-gold --with-local-prefix=/cbuild/slaves/oorts/crosstool-ng/builds/arm-linux-gnueabihf-linux/install/arm-linux-gnueabihf/libc --enable-c99 --enable-long-long --with-mode=thumb
Thread model: posix
gcc version 4.7.3 20130328 (prerelease) (crosstool-NG linaro-1.13.1-4.7-2013.04-20130415 - Linaro GCC 2013.04)

You can checkout U-boot source tree from Hardkernel's Github, please note that we distribute the Linux kernel in different branches for Android and other Linux distributions.

$ git clone --depth 1 https://github.com/hardkernel/linux.git -b odroidc-3.10.y-android
$ cd linux

$ git clone --depth 1 https://github.com/hardkernel/linux.git -b odroidc-3.10.y
$ cd linux

You must do kernel configuration for ODROID-C1, then start to build. Adding -j option on make command will help you to finish compiling faster.

$ make odroidc_defconfig
$ make <-j4>
$ make <-j4> modules

You have done to compile the Linux kernel (zImage), the device tree file (.dtb) and kernel modules (.ko). But in order to boot on ODROID-C1, you need uImage apart from zImage which have boot information and simply can make this.

$ make uImage

If you have some kernel drivers wish to include for your custom build, you can select the drivers easily in Linux kernel tree. make menuconfig will show you text based menus help you to select kernel drivers.

$ make menuconfig

Once you done selecting the drivers, exit from the menu screen. Then you can start kernel build with make again.

$ make <-j4>
$ make <-j4> modules

When you exit from kernel menu screen, you will have .config in the current directory what have changes for your custom build. You can back up this as a file, my_kernel.config for example, or can make a patch if you manage your own git.

$ cp .config arch/arm/configs/odroidc_defconfig
$ git add arch/arm/configs/odroidc_defconfig
$ git commit -s -m "blahblahblah"
$ git push

There are different instructions to install Linux kernel image and device tree for Android and Linux. Since Android loads both from a boot partition, we have to use fastboot to install into the dedicated partition. Please refer the partition table from here. In contrast, Linux boots by the instructions described in boot.ini the 1st FAT partition.

This is the instruction to install kernel image, uImage, to the boot card.

$ sudo fastboot flash boot <path/of/your/uImage>

This is to install a device tree file, meson8b_odroidc.dtb.

$ sudo fastboot flash dtb <path/of/your/meson8b_odroidc.dtb>

1. Plug the Boot-Device(eMMC or SD) into the USB memory CARD reader and Connect the USB memory CARD reader to your HOST PC(Linux OS).

2. Copy the uImage and DT((meson8b_odroidc.dtb) to the FAT partition(1st partition) in the Boot-Device.

$ mkdir -p mount
$ sudo mount /dev/sdc1 ./mount
$ sudo cp arch/arm/boot/uImage arch/arm/boot/dts/meson8b_odroidc.dtb ./mount && sync && sudo umount ./mount

3. Copy the driver modules to the EXT4 partition(2nd partition) in the Boot-Device.

$ sudo mount /dev/sdc2 ./mount
$ sudo make modules_install ARCH=arm INSTALL_MOD_PATH=./mount && sync && sudo umount ./mount
$ rm -rf mount