184 lines
7.6 KiB
Markdown
184 lines
7.6 KiB
Markdown
|
---
|
||
|
title: ASUS Chromebook C201
|
||
|
x-toc-enable: true
|
||
|
...
|
||
|
|
||
|
NOTE: support for this machine is dropped in recent Libreboot releases. It will
|
||
|
be re-added at a later date. For now, please use Libreboot 20160907 on this
|
||
|
machine.
|
||
|
|
||
|
NOTE: much of this page is outdated. for instance, it references cafe beverage
|
||
|
who later revealed herself to be Alyssa Rosenzweig, who then launched the
|
||
|
Panfrost project.
|
||
|
|
||
|
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.
|
||
|
|
||
|
Flashing instructions can be found at
|
||
|
[../install/\#flashrom](../install/#flashrom)
|
||
|
|
||
|
Google's intent with CrOS devices
|
||
|
==================================
|
||
|
|
||
|
CrOS (Chromium OS/Chrome OS) devices, such as Chromebooks, were not
|
||
|
designed with the intent of bringing more freedom to users. However,
|
||
|
they 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 CrOS 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.
|
||
|
|
||
|
CrOS devices 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.
|
||
|
|
||
|
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.
|
||
|
|
||
|
Debian GNU+Linux
|
||
|
----------------
|
||
|
|
||
|
<https://wiki.debian.org/InstallingDebianOn/Asus/C201> shows how to
|
||
|
install Debian.
|
||
|
|
||
|
Devuan GNU+Linux
|
||
|
----------------
|
||
|
|
||
|
<https://notabug.org/dimkr/devsus> produces bootable and installable
|
||
|
Devuan images.
|
||
|
|
||
|
Parabola GNU+Linux
|
||
|
------------------
|
||
|
|
||
|
See:
|
||
|
<https://lists.gnu.org/archive/html/libreboot/2015-12/msg00026.html>
|
||
|
|
||
|
In this discussion thread (on the old GNU Libreboot mailing lists), there are
|
||
|
instructions for installing Parabola on C201 and other rockchip chromebooks
|
||
|
supported by Libreboot.
|
||
|
|
||
|
Caution: Video acceleration requires a non-free blob, software rendering can be used instead.
|
||
|
=============================================================================================
|
||
|
|
||
|
The C201 has a Mali T GPU, which requires a non-free blob. A driver,
|
||
|
Tamil, was written, but its source code has not been released. The
|
||
|
developer has so-far [withheld
|
||
|
it](http://libv.livejournal.com/27461.html). Use software rendering to
|
||
|
avoid the blob instead. 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*.
|
||
|
|
||
|
As it is unlikely that Tamil will be released, the
|
||
|
[chai](https://notabug.org/cafe/chai) project is writing a driver as
|
||
|
well. Ask on IRC if you think you can contribute.
|
||
|
|
||
|
Caution: WiFi requires a non-free blob, a USB dongle can be used instead.
|
||
|
=========================================================================
|
||
|
|
||
|
These laptops have non-removeable (soldered on) M.2 Type 1216 card
|
||
|
with WiFi+Bluetooth, which requires non-free firmware to be loaded by
|
||
|
the Linux kernel in order to work.
|
||
|
|
||
|
The libreboot project recommends using an external USB wifi dongle that
|
||
|
works with free software. See
|
||
|
[\#recommended\_wifi](./#recommended_wifi).
|
||
|
|
||
|
There are 2 companies (endorsed by 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):
|
||
|
|
||
|
- [ThinkPenguin sells
|
||
|
them](https://www.thinkpenguin.com/gnu-linux/penguin-wireless-n-usb-adapter-gnu-linux-tpe-n150usb)
|
||
|
(company based in USA)
|
||
|
- [Tehnoetic sells
|
||
|
them](https://tehnoetic.com/tehnoetic-wireless-adapter-gnu-linux-libre-tet-n150)
|
||
|
(company based in Europe)
|
||
|
|
||
|
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:
|
||
|
[../../faq.md#firmware-ec](../../faq.md#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.
|
||
|
|
||
|
Depthcharge payload
|
||
|
===================
|
||
|
|
||
|
These systems do not use the GRUB payload. Instead, they use a payload
|
||
|
called depthcharge, which is common on CrOS devices. 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/spi.md](../install/spi.md) 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 CrOS devices make it easy. The screw
|
||
|
is such a stupidly simple idea, which all designs should implement.
|