Ubuntu Lucid on OLPC XO

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Introduction

This guide describes how to install Ubuntu 10.04 (Lucid Lynx) on the OLPC XO. The method of installing Ubuntu described herein is aimed at power users who know what they're doing and know what they want - but plain old folks are welcome to give it a try, of course. This guide solves the problem that earlier methods had with getting Upstart to work, now we won't have to take a step backwards to sysvinit.

Requirements

  • The Ubuntu 10.04 CD image: http://releases.ubuntu.com/10.04/ubuntu-10.04-desktop-i386.iso
  • A USB flashdrive or an SD card big enough to fit the Ubuntu system, 4 GB should work.
  • A computer other than the XO, to create the Ubuntu system on. We will be using a virtualisation software on this computer to create the Ubuntu image which will be written to the flashdrive/SD card. I will be using an Ubuntu system (surprise!) with VirtualBox. Qemu should work too.
  • A developer key, to unlock the XO bootloader.

Creating the Ubuntu image

  • First, you need to have permissions to access your USB flashdrive/SD card as a normal user:
$ sudo usermod -a -G disk <your username>

Now log out, and log back in for this to take effect.

  • If you are using VirtualBox, add your USB flashdrive or SD card as a virtual harddrive that we can install Ubuntu onto.
$ cd ~/.VirtualBox/HardDisks
$ VBoxManage internalcommands createrawvmdk -filename olpc-xo.vmdk -rawdisk /dev/sdX -register

...where sdX is your USB/SD drive.

  • With Qemu, the commandline option "-hda /dev/sdX" should do the trick.
  • Install Ubuntu as you normally would onto the USB/SD drive.

If you need guidance on how to operate your virtualization software or install Ubuntu in it, please look elsewhere - the Internet has plenty of guides on that.

Attention: Make sure to use the manual partition editor during the installation, and format the root partition as Ext3. Do not use the default setting of Ext4, as it is not yet supported by the OpenFirmware bootloader in the XO.
Also, do not create a swap partition. Flash drives die prematurely from the wear & tear of swapping.

When the installation is complete, you will boot into your new system for the first time in the virtual machine. This is a good time to install the latest and greatest packages and updates: 

$ sudo apt-get update
$ sudo apt-get upgrade

Adapting Ubuntu to the XO

The following is done while you're still in the virtual machine.

You might want to install the ubuntu-netbook packages. They give your desktop a new look, replacing your standard Gnome desktop with a slightly iPhone-inspired interface. The main menu and the desktop are replaced with a desktop-sized application launcher with nice, big icons. All windows are maximized to make good use of the small screen and take away the hassle of window manipulation. 

$ sudo apt-get install ubuntu-netbook

The most important fix, however, is to replace the Linux kernel. For some reason, the stock Ubuntu kernel doesn't work on the XO. (It seems to boot, judging by miscellaneous flashing LEDs on the computer, but the display is stuck on the OpenFirmware screen (even when unfrozen). Video driver issues?)

Make sure to get the binary package, and not the source. Example: http://dev.laptop.org/~kernels/olpc-2.6.31-xo1/kernel-2.6.31_xo1-20100504.1635.1.olpc.7223ce6.i586.rpm

If you're using a more recent version than this one, make sure to change all references to it accordingly in the commands below. 

$ sudo apt-get install rpm2cpio
$ cd /
$ sudo sh -c "rpm2cpio /home/user/Downloads/kernel-2.6.31_xo1-20100504.1635.1.olpc.7223ce6.i586.rpm | cpio -idmv"
$ sudo depmod 2.6.31_xo1-20100504.1635.1.olpc.7223ce6

For some reason, the WiFi firmware is messed up. Fix it thus: 

$ sudo ln -s /lib/firmware/libertas/usb8388_v9.bin /lib/firmware/usb8388.bin

Now, we need to include our new modules in the Ubuntu initrd: 

$ mkdir /tmp/initrd && cd /tmp/initrd
$ zcat /boot/initrd.img-2.6.xxxxxxx | cpio -idmv
$ cp -r /lib/modules/2.6.31_xo1-20100504.1635.1.olpc.7223ce6 lib/modules/
$ cp -r /lib/firmware/{libertas,usb8388.bin} lib/firmware/
$ sudo sh -c "find . | cpio -H newc -o | gzip > /boot/initrd.img-xo"

(Some people reported that they needed the WiFi firmware (libertas) in the initrd in order for the driver to work, so I included that for now)

  • If firmware security is enabled on your XO (it most likely is), you will need a developer key in order to boot anything but the stock Fedora/Sugar OS. Once you have your key, create a folder: "sudo mkdir /security", and save your develop.sig file there.

The last step is to create the Forth script that tells OpenFirmware how to boot our system. Save the following as /boot/olpc.fth: 

\ OpenFirmware boot script for Ubuntu
" sd:\boot\initrd.img-xo" to ramdisk
boot sd:\boot\vmlinuz-2.6.31_xo1-20100504.1635.1.olpc.7223ce6 ro root=LABEL=OLPCRoot rootdelay=30

This script is for booting from an SD card; if you use a USB drive, replace sd with u.

  • Now, shut down your virtual machine. It will soon be time to try out our creation on the XO!

Attention: You might have noticed that the root partition is referenced by its label in the boot script above. Thus, in order for the Linux kernel to find it, you need to give it the right label at this point: 

$ sudo tune2fs /dev/sdX1 -L OLPCRoot

Good luck!

Plug your drive into the XO and boot it up - with any luck, it might work! :]

Oops: For now, it seems that you have to hold down the "checkmark game button" when powering on. If you don't push the button, OpenFirmware will freeze the screen - and Ubuntu doesn't know how to unfreeze it. Adding "unfreeze" to the bootscript doesn't seem to help. Does anyone know why?

Just one more thing: it'd be awfully nice if you left a comment on the Discussion tab above. Just tell us whether it all went smoothly, or if something needs to be worked on. Thanks for contributing!

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