Chromium OS for Raspberry Pi

Initial notes:

• Don't expect to build this and have it work perfectly on a Raspberry Pi, it's a work-in-progress
• This guide will be much easier to follow if you've built Chromium OS before for another platform. If you've having trouble following it, try following the developer guide (linked before) to build an x86-generic image first, and then come back.
• If you want to help out, find me in #raspberrypi on Freenode IRC or submit a pull request

Prerequisites:

To get started, make sure you have the following:

• a 64-bit build machine, running Ubuntu version 10.04 (other versions/distros might work, but aren't supported, you're on your own)
• an account with sudo access
• at least 4GB of RAM (whilst you might be able to build with less, it'll be probably be painfully slow, especially when it comes to building Chrome)
• a fast Internet connection - you'll need to download several gigabytes of source code, if your connection is slow, that won't be fun

Get the code:

First, you'll need to download the Chromium OS source code. To learn do so, and also how to setup your environment, check out this link: http://www.chromium.org/chromium-os/developer-guide

Once you've downloaded the code and you've reached the "4.3 Select a board" step, continue below.

Add the overlay:

To build for the Raspberry Pi, you'll need to use the raspberrypi overlay provided by this repo. Until this is merged upstream into the Chromium OS project, you'll have to copy it manually across.

Find the folder named "overlays" in the "src" folder of the code you checked out. You'll see a number of folders with names starting "overlay-". Place the overlay-raspberrypi folder in this folder alongside the other overlays.

Toolchain setup:

For this step and all following steps you MUST be inside the CrOS chroot. Refer to developer guide section 4.2 if you're not sure how to do this. You only need to do this once (unless you nuke your chroot). To build/install the toolchain, we must be root. To become root, type:

sudo -i

Once you're root, build the toolchain by typing:

USE="-thumb -hardened hardfp" FEATURES="splitdebug" crossdev -S -t armv6j-cros-linux-gnueabi --ex-gdb

This might take some time, so go get a coffee. Once that command finishes successuflly, we don't need to be root anymore, so drop root by running:

exit

Board setup:

Once again, you only need to run this once (unless you nuke the chroot):

./setup_board --board=raspberrypi

If you want to re-create the board root, run:

./setup_board --board=raspberrypi --force

You'll probably want to set the "backdoor" password for a development image to let yourself into a shell when the UI isn't working, to do that, use the following command:

./set_shared_user_password

Once prompted, enter a password, then press enter. As above, you only need to do this once.

Building an image:

Before we can build an image, we need to build all the required packages. Enter the following command to build those (and pray everything compiles):

./build_packages --board=raspberrypi --withdev --nowithdebug --nousepkg --nowithautotest

This will take even longer than building the toolchain took. Go get several coffees, and maybe read a book.

Once all the packages have been successfully built, we can build a USB image by running the following command:

./build_image dev --board=raspberrypi --noenable_rootfs_verification