AllWinner A10 Initramfs Support and Linaro 12.07 Image

An initramfs is a minimal root filesystem that is loaded at an early stage of the boot process, before the rootfs partition is mounted. This is optional but is now used by many Linux distributions such as Ubuntu in order to speed up boot time among others things.

Up to recently, there was no support for this in the AllWinner A10 nightly builds, and there would be lot of error messages due to ureadahead process with Ubuntu, but I’ve changed that by:

  • Using a boot.scr file (U-Boot Script) for each supported device in order to either follow the default init boot method or do an initramfs boot if uInitrd file is present in the FAT partition.
  • Adding a script (a1x-initramfs.sh) to generate and install uInitrd initramfs in the rootfs. The initramfs can’t be generated at build time since the hardware packs are (mostly) distribution agnostic. If you want an initramfs, you’ll need to run the script manually, as initramfs support is optional.

I mainly followed and adapted the instructions provided by Peter (j1nx) for boot.scr and the initramfs.

As an example, I’ll generate a Linaro ALIP (ARM Linux Internet Platform) 12.07 SD card for Mele A1000 with VGA output.

First let’s download the latest hardware pack from http://dl.linux-sunxi.org/nightly/latest/ in a Linux PC e.g.:


as well as a1x-media-create.sh script and Linaro ALIP 12.07 rootfs:


We’ve got all we need. Let’s create a bootable SD card the usual way:


Now let’s insert the SD card into the Mele A1000 and boot as usual. You should notice a lot of error messages:


Those are due to the lack of initramfs, but are not critical. The boot from power to LXDE took 1m 8s.

I’ll run all the next command as root in the serial console, if you want to run those with a terminal window in LXDE as linaro user, simply run add “sudo”to the commands.

Let’s check the content of the FAT partition:


There’s the u-boot script, script.bin and the kernel image.

Time to generate the initramfs, simply run a1x-initramfs.sh:


uInitrd file has been properly generated in the FAT partition:


Let’s reboot. All errors messages are gone and it just took 38s to boot to LXDE.

This script currently only support Ubuntu / Debian. Feel free to update it to support other distributions.

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