PrawnOS

A build system for making blobless Debian and mainline Linux kernel for the Asus c201 Chromebook with support for dmcrypt/LUKS root partition encryption

Build Debian filesystem with:

• No blobs, anywhere.
• Sources from only main, not contrib or non-free which keeps Debian libre.
• Currently PrawnOS supports xfce and lxqt as choices for desktop enviroment.
• full root filesystem encryption

Build a deblobbed mainline kernel with:

• Patches for reliable USB.
• Patches to support the custom GPT partition table required to boot.
• Support for Atheros AR9271 and AR7010 WiFi dongles.
• Support for CSR8510 (and possibly other) bluetooth dongles.

Don't want to use one of the two USB ports for the WiFi dongle? check out this

Why

Combined with Libreboot, an AR9271 or AR7010 WiFi dongle, and a libre OS (like Debian with the main repos, the one built by PrawnOS) the Asus c201 is a fully libre machine with no blobs, or microcode, or Intel Management Engine.

WARNING: flashing libreboot to asus c201 chromebooks that have recently been updated to a new version of chromeOS may leave the device in a non-functional (bricked) state.

If you do not have a way to recover your device by using an external flasher as described in the second part of this page https://libreboot.org/docs/install/c201.html it would be safest to wait until this issue is resolved. I have opened a bug with libreboot, which can be found here https://notabug.org/libreboot/libreboot/issues/666 If you have any information that may help with debugging, please post it there.

The install process of PrawnOS does not flash your bios, so it is safe to use along with the default coreboot/depthcharge and does not risk bricking your device

What is a blob?

In the world of free and open-source software, the term is used to refer to proprietary device drivers, which are distributed without their source code, exclusively through binary code; in such use, the term binary blob is common. wikipedia

Image Download

If you don't want to or can't build the image, you can find downloads under https://github.com/SolidHal/PrawnOS/releases

Dependencies

Building PrawnOS has been tested on Debian 10 Buster (in a VM) stretch doesn't work as the version of gcc-arm-none-eabi is too old This is the only build enviroment that is supported. These packages are required:

	apt install --no-install-recommends --no-install-suggests parted cgpt git \
	gawk device-tree-compiler vboot-kernel-utils gcc-arm-none-eabi u-boot-tools \
	gcc make libc-dev wget g++ cmake binfmt-support qemu-user-static debootstrap \
	lzip libssl-dev libncurses-dev flex bison sudo patch bc

Build

Clone this Git repo.

Build the PrawnOS-...-.img by running sudo make image

This has only been tested on a Debian stretch VM, and borrows some components from the host system to setup apt/debootstrap during the build process so I would recommend using a Debian Stretch VM to avoid any issues.

Write to a flash drive or SD card

Write the 2GB image to a flash drive. Make sure to replace $USB_DEVICE with the desired target flash drive or SD card device. If you're not familiar with dd, check out Debian's how to page https://www.debian.org/CD/faq/#write-usb

sudo dd if=PrawnOs-*-c201-libre-2GB*.img of=/dev/$USB_DEVICE bs=50M; sync

Installing

There are two ways to use PrawnOS.

The first option is to boot from the external USB or SD device you wrote the image to. click here

• Booting from an external device allows you to try PrawnOS without removing Chrome OS or whatever Linux you are running on your internal storage (emmc), but it is a much slower experience as the c201 only has USB 2.0.

The second and, recommended, option is to install it on your internal storage (emmc) click here

• This is faster, and frees up a USB port.

Install to Internal drive (emmc)

Now on the C201, press control+u at boot to boot from the USB drive.

If you are running stock coreboot and haven't flashed Libreboot, you will first have to enable developer mode and enable USB booting. A quick search should get you some good guides, but if you're having issues feel free to open an issue here on github.

At the prompt, login as root. The password is blank.

WARNING! THIS WILL ERASE YOUR INTERNAL EMMC STORAGE (your Chrome OS install or other Linux install and all of the associated user data) Make sure to back up any data you would like to keep before running this.

If you would like to install it to the internal emmc storage run:

cd /
./InstallToInternal.sh

This will show a bunch of scary red warnings that are a result of the emmc (internal storage) being touchy and the kernel message level being set low for debugging. They don't seem to effect anything long-term.

Setting up root partition encryption

PrawnOS supports encrypting the full root partition with the use of a custom initramfs and dmcrypt/LUKS Type "Yes" at the prompt, then enter the password you would like to use and verify it You will then be prompted one more time to enter your encryption password to mount and setup the filesystem If you are curious how the initramfs, and root partition encryption work on PrawnOS check out the Initramfs and Encryption section in DOCUMENTATION.md

The device will then reboot. If you are running the stock coreboot, you will have to press control+d or wait 30 seconds past the beep to boot to the internal storage.

If you are running Libreboot, it should boot to the internal storage by default. If it doesn't, turn off the device and remove the flash drive before turning it on again.

Now login as root again and run:

cd /InstallResources
./InstallPackages.sh

Which installs either the xfce4 or the lxqt desktop enviroment, sound, trackpad, and Xorg configurations as well as prompts you to make a new user that automatically gets sudo privileges.

If it asks you about terminal encoding and/or locale, just hit enter. The default works for both.

When finished, it will reboot once again placing you at a login screen.

Congratulations! Your computer is now a Prawn! https://sprorgnsm.bandcamp.com/track/the-prawn-song

Connecting to WiFi in a basic environment

If you just want a basic environment without xfce or lxqt can skip running InstallPackages.sh. You can connect to WiFi using wpa_supplicant by running the following commands:

wpa_passphrase <Network_name> <network_password> > wpa.conf
wpa_supplicant -i wlan0 -c wpa.conf

Now switch to another tty by pressing ctrl+alt+f2 Login as root, and run

dhclient wlan0

When that finishes, you should have access to the internet.

Install To USB drive or SD card

Now on the C201, press control+u at boot to boot from the USB drive.

If you are running stock coreboot and haven't flashed Libreboot, you will first have to enable developer mode and enable USB booting. A quick search should get you some good guides, but if you're having issues feel free to open an issue here on github.

When it boots, login as root. The password is blank.

If you simply want a basic Linux environment with no desktop environment or window manager:

Make sure it's the only storage device plugged in, and run this script to expand the partition and filesystem to the full USB drive. This will reboot when complete, so you'll have to press control+u again to boot to the external media.

cd /InstallResources/
./ExpandExternalInstall.sh

Congratulations: you are done! Welcome to PrawnOS. You should probably change the root password and make a user, but I'm not your boss or anything so I'll leave that to you. If you want a quick guide on how to connect to WiFi, check out this down below

For everyone else, two scripts need to be run.

The first expands the partition and filesystem to use the entire drive. Make sure you only have one USB or SD storage device plugged into the machine. This will reboot when complete, so you'll have to press control+u again to boot to the external media. Run:

cd /InstallResources/
./ExpandExternalInstall.sh

You can verify it worked by running df -h after the reboot. The original /dev/root/ filesystem was only ~2GB Then run this script which installs either the xfce4 or the lxqt desktop enviroment, sound, trackpad, and Xorg configurations as well as prompts you to make a new user that automatically gets sudo privileges.

If it asks you about terminal encoding and/or locale, just hit enter. The default works for both.
When finished, it will reboot once again placing you at a login screen.

./InstallPackages.sh

This will take a while; USB 2.0 is slow. Welcome to PrawnOS. If you like it, I would suggest installing it to your internal storage (emmc).

Upgrading the kernel

The script UpgradeKernel.sh located in /InstallResources can be ran be used to copy the kernel, modules, and ath9k firmware from a newer version of PrawnOS running on a USB drive or SD card onto an older version of PrawnOS installed on the laptops internal emmc storage.

To use it, write the new PrawnOS image to a USB drive or SD card, boot the laptop to it by pressing control+u at boot, navigate to the /InstallResources folder, and run the script.

Documentation

Some useful things can be found in DOCUMENTATION.md

Make options, developer tools

(All of these should be run as root or with sudo to avoid issues) The makefile automates many processes that make debugging the kernel or the filesystem easier. To begin with:

make kernel_config cross compiles make menuconfig Cross compiling is required for any of the Linux kernel make options that edit the kernel config, as the Linux kernel build system makes assumptions that change depending on what platform it is targeting.

make kernel builds just the kernel

make filesystem builds the -BASE filesystem image with no kernel

make initramfs builds the PrawnOS-initramfs.cpio.gz, which can be found in /build

make image builds the initramfs image, builds the kernel, builds the filesystem if a -BASE image doesn't exist, and combines the two into a new PrawnOS.img using kernel_inject

make kernel_inject Injects a newly built kernel into a previously built PrawnOS.img located in the root of the checkout. Usually, this will be a copy of the -BASE image made by make filesystem. Only use this if you already have a built kernel and filesystem -BASE image.

You can use the environment variable PRAWNOS_SUITE to use a Debian suite other than Buster. For example, to use Debian stretch, you can build with sudo PRAWNOS_SUITE=stretch make image. Note that only stretch and buster have been tested.

You can use the environment variable PRAWNOS_DEBOOTSTRAP_MIRROR to use a non-default Debian mirror with debootstrap. For example, to use Debian's Tor onion service mirror with debootstrap, you can build with sudo PRAWNOS_DEBOOTSTRAP_MIRROR=http://vwakviie2ienjx6t.onion/debian make image.

GPU Support

Watch this link for GPU support: https://gitlab.freedesktop.org/panfrost and this one for progress updates: https://rosenzweig.io/blog/gpu-feed.xml

Build the WiFi dongle into the laptop

Sick of having a USB dongle on the outside of your machine for wi-fi? Want to be able to use two USB devices at once without a hub? Check out the instructions here: https://github.com/SolidHal/AsusC201-usb-wifi-from-webcam Warning: decent soldering skills required

Troubleshooting

The pulse audio mixer will only run if you are logged in as a non-root account. This is an issue (feature?) of pulse audio

Credits and Legal Information

Thanks to dimkr for his great devsus scripts for the Chrome OS 3.14 kernel, from which PrawnOS took much inspiration https://github.com/dimkr/devsus

Because PrawnOS started as a fork of devsus-3.14, some of this repo's ancient history can be found at https://github.com/SolidHal/devsus/tree/hybrid_debian

PrawnOS is free and unencumbered software released under the terms of the GNU General Public License, version 2; see COPYING for the license text. For a list of its authors and contributors, see AUTHORS.