Table of Contents

Cross-compiling an Allwinner ARM Linux kernel on Debian amd64

0. Before you begin

In case you just want some particular kernel feature to be enabled in the config, check out my pre-built kernels, maybe these will already have what you need (and save you some time compiling).

1. Install various tools you will need

apt-get install git build-essential fakeroot kernel-package u-boot-tools zlib1g-dev libncurses5-dev

2. Install the Emdebian toolchain

Into your /etc/apt/sources.list add:1) 

deb http://www.emdebian.org/debian/ unstable main

Then: 

apt-get update
apt-get install emdebian-archive-keyring
apt-get install gcc-4.7-arm-linux-gnueabihf
ln -sf `which arm-linux-gnueabihf-gcc-4.7 ` /usr/local/bin/arm-linux-gnueabihf-gcc

# ^ FIXME: find/fix why the version-less filename is not created automatically

3. Get the kernel source code

git clone https://github.com/linux-sunxi/linux-sunxi linux-sunxi
cd linux-sunxi
git checkout sunxi-3.4

4. Get a kernel config

I suggest my configs available at:

Save the config file you downloaded as ”.config” in the kernel source directory.

If you wish to check and adjust settings, run: 

ARCH=arm make menuconfig

5. Compile your kernel

In the kernel source directory do: 

export ARCH=arm
export DEB_HOST_ARCH=armhf

export CONCURRENCY_LEVEL=`grep -m1 cpu\ cores /proc/cpuinfo | cut -d : -f 2`
fakeroot make-kpkg --arch arm --cross-compile arm-linux-gnueabihf- --initrd --append-to-version=-custom1 kernel_image kernel_headers

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- EXTRAVERSION=-custom1 uImage
cp arch/arm/boot/uImage ../uImage

You can save the above as a script for convenience. You can also replace custom1 with something else, e.g. your nickname and a number that represents the order number of the new package of this particular kernel (as it is common to recompile the same kernel version a few times to get everything just right in the config, or to try out different patches).

After the compilation, in the directory one level above the kernel source tree, you will get:

  • linux-image-*.deb, a Debian package with the kernel;
  • linux-headers-*.deb, a Debian package with kernel headers (mostly unneeded);
  • an uImage, the kernel itself in the u-boot compatible format.

6. Install and test your kernel

Now you will need to:

  • copy linux-image-*.deb to your target device and install it there;
  • copy uImage into the device's /boot/ partition.

Until you have ensured that the new kernel works, keep the previous uImage that already was there, just rename it into something different (e.g. uImage.bak). In case your new kernel doesn't boot, you can simply insert your the SD card into some other device, mount the boot partition and restore the previous uImage.

Various related articles and HOWTOs

1) more details at http://emdebian.org/crosstools.html

a10/cross-compile-kernel.txt · Last modified: 2016-03-25 05:57 UTC by rm