% 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!

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/#flashrom

Google's intent with CrOS devices
Considerations about ChromeOS and free operating systems
Caution: Video acceleration requires a non-free blob, software rendering can be used instead.
Caution: WiFi requires a non-free blob, a USB dongle can be used instead.
EC firmware is free software!
No microcode!
Depthcharge payload
Flash chip write protection: the screw

Google's intent with CrOS devices {#googlesintent}

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 {#os}

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.

TODO: instructions for Devuan

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

The Tamil driver source code for the onboard Mali T GPU is not released. The developer has so-far withheld it. 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 Tamil developer wrote this blog post, which sheds light on the story: http://libv.livejournal.com/27461.html,http://libv.livejournal.com/27461.html.

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

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 #recommended_wifi.

There are 2 companies (endorsed by Creative Commons, 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 (company based in USA)
Tehnoetic sells them (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! {#ec}

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! {#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 {#depthcharge}

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 {#thescrew}

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 CrOS devices make it easy. The screw is such a stupidly simple idea, which all designs should implement.

These instructions are for installing Libreboot to the ASUS Chromebook C201. Since the device ships with Coreboot, the installation instructions are the same before and after flashing Libreboot for the first time.

If you are using libreboot_src or git, then make sure that you built the sources first (see ../git/#build).

Look at the list of ROM images to see which image is compatible with your device.

Libreboot can be installed internally from the device, with sufficient privileges. The installation process requires using Google's modified version of flashrom, that has support for reflashing the Chromebook's SPI flash. Otherwise, flashing externally will work with the upstream flashrom version.

Google's modified version of flashrom is free software and its source code is made available by Google: flashrom.\ It is not distributed along with Libreboot yet. However, it is preinstalled on the device, with ChromeOS.

Installing Libreboot internally requires sufficient privileges on the system installed on the device.\ When the device has ChromeOS installed (as it does initially), it is necessary to gain root privileges in ChromeOS, to be able to access a root shell.

Gaining root privileges on ChromeOS
Preparing the device for the installation
- Configuring verified boot parameters
- Removing the write protect screw
[Installing Libreboot to the SPI flash]()
- Installing Libreboot internally, from the device
- Installing Libreboot externally, with a SPI flash programmer
Debian GNU+Linux is recommended for this device

Gaining root privileges on ChromeOS In order to gain root privileges on ChromeOS, developer mode has to be enabled from the recovery mode screen and debugging features have to be enabled in ChromeOS.

Instructions to access the recovery mode screen and enabling developer mode are available on the page dedicated to depthcharge.

Once developer mode is enabled, the device will boot to the developer mode screen. ChromeOS can be booted by waiting for 30 seconds (the delay is shortened in Libreboot) or by pressing Ctrl + D

After the system has booted, root access can be enabled by clicking on the Enable debugging features link. A confirmation dialog will ask whether to proceed.\ After confirming by clicking Proceed, the device will reboot and ask for the root password to set. Finally, the operation has to be confirmed by clicking Enable.

After setting the root password, it becomes possible to log-in as root. A tty prompt can be obtained by pressing Ctrl + Alt + Next. The Next key is the one on the top left of the keyboard.

Preparing the device for the installation Before installing Libreboot on the device, both its software and hardware has to be prepared to allow the installation procedure and to ensure that security features don't get in the way.

Configuring verified boot parameters {#configuring_verified_boot_parameters}

It is recommended to have access to the developer mode screen and to configure the following verified boot parameters:

Kernels signature verification: disabled
External media boot: enabled

Those changes can be reverted later, when the device is known to be in a working state.

Removing the write protect screw {#removing_write_protect_screw}

Since part of the SPI flash is write-protected by a screw, it is necessary to remove the screw to remove the write protection and allow writing Libreboot to the read-only part of the flash.

To access the screw, the device has to be opened. There are 8 screws to remove from the bottom of the device, as shown on the picture below. Two are hidden under the top pads. After removing the screws, the keyboard plastic part can be carefully detached from the rest. Beware: there are cables attached to it! It is advised to flip the keyboard plastic part over, as shown on the picture below. The write protect screw is located next to the SPI flash chip, circled in red in the picture below. It has to be removed.

The write protect screw can be put back in place later, when the device is known to be in a working state.

Installing Libreboot to the SPI flash {#installing_libreboot_spi_flash}

The SPI flash (that holds Libreboot) is divided into various partitions that are used to implement parts of the CrOS security system. Libreboot is installed in the read-only coreboot partition, that becomes writable after removing the write-protect screw.

Installing Libreboot internally, from the device {#installing_libreboot_internally}

Before installing Libreboot to the SPI flash internally, the device has to be reassembled.

All the files from the veyron_speedy release (or build) have to be transferred to the device.

The following operations have to be executed with root privileges on the device (e.g. using the root account). In addition, the cros-flash-replace script has to be made executable:

# chmod a+x cros-flash-replace

The SPI flash has to be read first:

# flashrom -p host -r flash.img\

Note: it might be a good idea to copy the produced flash.img file at this point and store it outside of the device for backup purposes.

Then, the cros-flash-replace script has to be executed as such:

# ./cros-flash-replace flash.img coreboot ro-frid

If any error is shown, it is definitely a bad idea to go further than this point.

The resulting flash image can then be flashed back:

# flashrom -p host -w flash.img

You should also see within the output the following:\ "Verifying flash... VERIFIED."

Shut down. The device will now boot to Libreboot.

Installing Libreboot externally, with a SPI flash programmer {#installing_libreboot_externally}

Before installing Libreboot to the SPI flash internally, the device has to be opened.

The SPI flash is located next to the write protect screw. Its layout is indicated in the picture below. Note that it is not necessary to connect WP# since removing the screw already connects it to ground. Before writing to the chip externally, the battery connector has to be detached. It is located under the heat spreader, that has to be unscrewed from the rest of the case. The battery connector is located on the right and has colorful cables, as shown on the picture below.

All the files from the veyron_speedy release (or build) have to be transferred to the host.

The following operations have to be executed with root privileges on the host (e.g. using the root account). In addition, the cros-flash-replace script has to be made executable:

# chmod a+x cros-flash-replace

The SPI flash has to be read first (using the right spi programmer):

# flashrom -p *programmer* -r flash.img