On Thu, Jan 30, 2014 at 9:53 AM, James MacMahon <jwm@operand.ca> wrote:
Hi everyone,

Quick question: what is the status of coreboot + some payload being used with
the Samsung XE303CE ARM Chromebook (snow)?

The page at [http://www.coreboot.org/Chromebooks] says 'Snow has das U-Boot
nativly installed, but a coreboot port is available.', and the page at
[http://www.coreboot.org/Supported_Motherboards] has 'Google Snow - Samsung
Exynos 5250' under the 'Motherboards supported in coreboot', but I haven't been
able to find any blog / example of anyone actually flashing coreboot + some
payload and booting their Chromebook like a regular computer.

Right now it's close, but not quite close enough to be useful. The coreboot code should work, however there are some missing pieces that make it difficult to use in a meaningful manner:

- We don't have a generic payload to use with coreboot on this platform. The earlier work was done using Depthcharge which is a small payload specific for booting ChromeOS (with its verified boot mechanism and such). There is some (unfinished?) work to port FILO over, but I don't know what the status is. You could also try using a Linux kernel as a payload, but that has yet to be tried on this particular platform.

- To get serial console output, you need a debug board for Chromebooks which is unfortunately not easy to come by. Due to this limitation, if you are really intent on doing coreboot development on ARM it might be better to start with a more readily hackable platform such as the Cubieboard or Beaglebone.

It seems like there is a port available but no one has tried it from start to
finish on the ARM Chromebook (where my definition of finish in this context is
'booting with coreboot to stock Debian Linux', for example). I'm very keen on
doing this myself, and was hoping to find some example that I could read through
or even follow. This whole process of flashing a new BIOS is very new to me, and
I'm wary because of the potential to easily brick my device (however I'm not
scared off by reflashing or external chip programming if it comes to it, I'd
just like to avoid it).

There are a few wiki pages out there which detail the steps necessary to boot Debian/Ubuntu with the U-Boot firmware that ships with the device. Here is one from debian.org: https://wiki.debian.org/InstallingDebianOn/Samsung/ARMChromebook

For most people I would recommend that approach since it's a lot less risky and better tested.

David Hendricks (dhendrix)
Systems Software Engineer, Google Inc.