ASUS Chromebook C201

This is a chromebook, using the Rockchip RK3288 SoC. It uses an ARM CPU, and has free EC firmware (unlike some other laptops). More RK3288-based laptops will be added to libreboot at a later date.

Paul Kocialkowski, a Replicant developer, ported this laptop to libreboot. Thank you, Paul!

NOTE: This board is unsupported in libreboot 20150518. To use it in libreboot, for now, you must build for it from source using the libreboot git repository. Note that we recommend building for it from an x86 host, until libreboot's build system is modified accordingly.

More info will be added later, including build/installation instructions. The board is supported in libreboot, however, and has been confirmed to work.

Flashing instructions can be found at ../install/index.html#flashrom

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Google's intent with Chromebooks

Chromebooks were not designed with the intent of bringing more freedom to users. However, Chromebooks run with a lot of free software at the boot software and embedded controller levels, since free software gives Google enough flexibility to optimize various aspects such as boot time and most importantly, to implement the Chromebook security system, that involves various aspects of the software. Google does hire a lot of Coreboot developers, who are generally friendly to the free software movement and try to be good members of the free software community, by contributing code back.

Chromebooks are designed (from the factory) to actually coax the user into using proprietary web services (SaaSS) that invade the user's privacy (ChromeOS is literally just the Google Chrome browser when you boot up, itself proprietary and comes with proprietary add-ons like flash. It's only intended for SaaSS, not actual, real computing). Google is even a member of the PRISM program, as outlined by Edward Snowden. See notes about ChromeOS below. The libreboot project recommends that the user replace the default ChromeOS with a distribution that can be used in freedom, without invading the user's privacy.

We also use a similar argument for the MacBook and the ThinkPads that are supported in libreboot. Those laptops are supported, in spite of Apple and Lenovo, companies which are actually hostile to the free software movement.

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Considerations about ChromeOS and free operating systems

This laptop comes preinstalled (from the factory) with Google ChromeOS. This is a GNU/Linux distribution, but it's not general purpose and it comes with proprietary software. It's designed for SaaSS. Libreboot recommends that users of this laptop replace it with another distribution.

No FSF-endorsed distros available

The FSF has a list of distributions that are 100% free software. None of these are confirmed to work on ARM chromebooks yet. Parabola looks hopeful: https://www.parabola.nu/news/parabola-supports-armv7/

The libreboot project would like to see all FSF-endorsed distro projects port to these laptops. This includes Trisquel, GuixSD and others. And ProteanOS. Maybe even LibreCMC. The more the merrier. We need them, badly.

We need these distributions to be ported as soon as possible.

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Caution: Video acceleration requires a non-free blob, software rendering can be used instead.

The lima driver source code for the onboard Mali GPU is not released. The developer withheld it for personal reasons. Until that is released, the only way to use video (in freedom) on this laptop is to not have video acceleration, by making sure not to install the relevant blob. Most tasks can still be performed without video acceleration, without any noticeable performance penalty.

In practise, this means that certain things like games, blender and GNOME shell (or other fancy desktops) won't work well. The libreboot project recommends a lightweight desktop which does not need video acceleration, such as XFCE or LXDE.

The lima developer wrote this blog post, which sheds light on the story: http://libv.livejournal.com/27461.html

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Caution: WiFi requires a non-free blob, a USB dongle can be used instead.

These laptops have non-removeable (soldered on) WiFi chips, which require non-free firmware in the Linux kernel in order to work.

The libreboot project recommends using an external USB wifi dongle that works with free software. See index.html#recommended_wifi.

There are 2 companies (endorsed by the Free Software Foundation, under their Respects your Freedom guidelines), that sell USB WiFi dongles guaranteed to work with free software (i.e. linux-libre kernel):

These wifi dongles use the AR9271 (atheros) chipset, supported by the free ath9k_htc driver in the Linux kernel. They work in linux-libre too.

EC firmware is free software!

It's free software. Google provides the source. Build scripts will be added later, with EC sources provided in libreboot, and builds of the EC firmware.

This is unlike the other current libreboot laptops (Intel based). In practise, you can (if you do without the video/wifi blobs, and replace ChromeOS with a distribution that respects your freedom) be more free when using one of these laptops.

The libreboot FAQ briefly describes what an EC is: http://libreboot.org/faq/#firmware-ec

No microcode!

Unlike x86 (e.g. Intel/AMD) CPUs, ARM CPUs do not use microcode, not even built in. On the Intel/AMD based libreboot systems, there is still microcode in the CPU (not considered problematic by the FSF, provided that it is reasonably trusted to not be malicious, since it's part of the hardware and read-only), but we exclude microcode updates (volatile updates which are uploaded at boot time by the boot firmware, if present), which are proprietary software.

On ARM CPUs, the instruction set is implemented in circuitry, without microcode.

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Depthcharge payload

These systems do not use the GRUB payload. Instead, they use a payload called depthcharge, which is common on Chromebooks. This is free software, maintained by Google.

Flash chip write protection: the screw

It's next to the flash chip. Unscrew it, and the flash chip is read-write. Screw it back in, and the flash chip is read-only. It's called the screw.

The screw is accessible by removing other screws and gently prying off the upper shell, where the flash chip and the screw are then directly accessible. User flashing from software is possible, without having to externally re-flash, but the flash chip is SPI (SOIC-8 form factor) so you can also externally re-flash if you want to. In practise, you only need to externally re-flash if you brick the laptop; read ../install/bbb_setup.html for an example of how to set up an SPI programmer.

Write protection is useful, because it prevents the firmware from being re-flashed by any malicious software that might become executed on your GNU/Linux system, as root. In other words, it can prevent a firmware-level evil maid attack. It's possible to write protect on all current libreboot systems, but chromebooks make it easy. The screw is such a stupidly simple idea, which all laptop designs should implement.

Copyright © 2015 Francis Rowe <info@gluglug.org.uk>
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