Acer C710 Chromebook

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The following is a work in progress guide to getting Arch working on the $200 Acer C7 Chromebook.

For now you'll need a second computer already running *nix. If you're already running ChrUbuntu on your C7 then you can just skip to creating your own Arch image.

Installing Arch on an Acer C7 Chromebook

At present, Arch runs well on the C7. For information on 64bit installs first see Installing a x86_64 kernel. "Patches welcome" for custom or modded x86_64 Chromium kernels. The default install is 32bit due to the stock / stable channel's kernel.

Warning: *BACK UP YOUR DATA.*

Seriously. All of it. Somewhere *other* than on the device - the entire data partition will be purged a couple times over during the install process. USB keys, Google Drive, printed paper messages stored in bottles, something.

Enabling Dev Mode

First step is to enable Dev mode on the system so we can run some unsigned code. This will wipe all your data!

To enter Dev Mode:

  • Press hold down the Esc+F3 (Refresh) keys, and press the Power button.
This enters recovery mode,
  • Now press Ctrl+d (there's no prompt). It will ask you to confirm, then the system will reboot into dev-mode.
Dev Mode will always show the scary boot screen and you'll need to press Ctrl+d or wait 30 seconds to continue booting.
Note: If you ever need to hard reset, press the Esc+F3 (Refresh) combo. This will hard reset the system much like the small reset buttons on the front of tower PCs. The same warnings as on towers apply - the OS has no chance to save itself from this, and data loss is possible. You've been warned.

See Also: [1]

Install ChrUbuntu

While it sounds completely backwards to install Ubuntu on our Chromebook just to install Arch, at present it's the most automated and safe way. Scripts are in work-in-progress stages to try mashing the ChrUbuntu installer with arch-bootstrap; stay tuned for details if they arrive.

  • After enabling dev mode on your Chromebook, boot to the ChromeOS setup screen. Set keyboard layout, language, and connect to a network. Do *not* log in to an account.
  • Press Ctrl+Alt+F2 and login as "chronos"
  • Bring up a bash prompt
# bash
  • Download Chrubuntu installer and run it.
# curl -L -O git.io/pikNcg
# sudo bash ./pikNcg
Here is where you set the partition sizing for what will eventually be your Arch install. For example, I told the script "90", so Arch would be using the majority of my 128GB M4 SSD
  • Wait for the system reboot
  • Wait 3-5 minutes for the system "repair" job to run
  • Reset keyboard layout, language, and reconnect to a network. Still don't log in to an account.
  • Ctrl+Alt+F2 again, log in as "chronos" again
  • Bring up a bash prompt (again)
# bash
  • Download ChrUbuntu installer and run it. (again)
# curl -L -O git.io/pikNcg
# sudo bash ./pikNcg
  • Let the ChrUbuntu installer run. You'll get asked a few setup questions, it's safe to just hit Enter for everything as we'll never let Ubuntu see light of day.
  • While that installs, let's install Arch on our spare *nix box!
Note: When the installer finishes, it will ask you to press Enter to reboot. DO NOT DO THIS. Instead hit Ctrl+C to drop back to a shell. You have been warned.

Create Image File

  • First we need to create an Arch Image to do things with. This can be done an any *nix box.
# truncate -s 1G arch.img

Convert Image to A Partition

  • Convert image to a ext4 filesystem.
# mkfs.ext4 -m 1 arch.img
  • Mount image to install to
# mkdir /mnt/arch_install
# mount arch.img /mnt/arch_install

Install Arch on The New Image

At this point, run through the Installation Guide as you normally would. I strongly recommend doing this from a system with the Arch install scripts package installed; while this is a doable process with misc *nix systems (many of such processes are well documented here on the Wiki), it's going to be much smoother with the install scripts.

For 32 bit (x86),

# pacstrap /mnt/arch_install base base-devel --arch i686
Note: The `--arch i686` part is important if you're on the stock stable channel which currently uses a 32bit-PAE kernel.

For 64 bit (x64)

# pacstrap /mnt/arch_install base base-devel --arch x86_64

When setting up fstab, you'll need to mount "/dev/sda7" at "/". UUIDs aren't really an option here as data is about to get sorted all over the place.

Copy Arch Image to C7

Here's where things start to become a mess. By now you should have a ready-to-go ChrUbuntu install that you did not reboot into yet (meaning you're back at the bash shell in ChromeOS), and a ready-to-go Arch install on the arch.img file. You'll need to find a way to get this arch.img file to the Chromebook - be it a USB HDD, uploading it somewhere, SSHFS, whatever, make it happen.

  • Copy the Arch image to the Chromebook.
  • Create working directories.
# mkdir mnt mnt2 mnt3 backup
  • If your Arch image is on a USB key or drive, run "mount /dev/sdb1 mnt" (replacing /dev/sdb1 with the identifier of your USB drive according to ChromeOS). Then run "mount mnt/arch.img mnt2" (replacing arch.img with the name of your Arch image).
  • Otherwise, I'm assuming your Arch image was downloaded to the Chromebook somehow. So run "mount /path/to/arch.img mnt2"
  • Mount Ubuntu's root at mnt3.
# mount /dev/sda7 mnt3
  • Copy all firmware and kernel modules, which we'll need to successfully boot Arch.
# cp -a mnt3/lib/{firmware,modules} backup/
  • Save all module configs.
# cp -a mnt3/etc/modprobe.d/*.conf backup/
  • Remove old Ubuntu install
# rm -rf mnt3/*
Warning: Make 100% certain you typed "mnt3/*" and not some other mountpoint or you may toast your USB stick or Arch install.
  • Copy your Arch install off to what was Ubuntu's root directory.
# cp -a mnt2/* mnt3/
  • Restore module configs.
# cp -a backup/*.conf mnt3/etc/modprobe.d/

If running x86

  • Run "cp -a backup/modules/* mnt3/lib/modules/". This will restore kernel modules.

If running x86_64

# wget http://grayhatter.com/C7/zgb-x64-modules.tar.bz2
# tar xf zgb-x64-modules.tar.bz2
# sudo cp -R 3.4.0 mnt3/lib/modules/
  • Restore kernel firmwares.
# cp -a backup/firmware mnt3/lib/
  • Copy CGPT to arch so we can boot back and fourth.
# cp /usr/bin/cgpt mnt3/usr/bin/
# mkdir mnt3/usr/bin/old_bins
# cp /usr/bin/old_bins/cgpt mnt3/usr/bin/old_bins
  • "umount" mnt3, mnt2, and mnt. In that order.

Installing a 64bit Kernel

  • You have two choices here, the official and unofficial way. The 64bit kernels can be used with a 64 or 32bit filesystem.
  • Official:
  • You can simply login on your Chromebook and go to chrome://help , then change the channel from stable to Dev.
  • To make sure you have a 64bit kernel(and currently only 32bit ChromeOS FS), type:
# sudo modprobe configs && zcat /proc/config.gz | grep CONFIG_64BIT
  • If you have a 64bit kernel you will see the output CONFIG_64BIT=y.

Or

  • Unofficial:
  • Run these commands from within ChromeOS before rebooting.
# wget http://grayhatter.com/C7/zgb-x64-kernel-partition.bz2
# bunzip2 zgb-x64-kernel-partition.bz2
# use_kernfs="zgb-x64-kernel-partition"
# target_kern="/dev/sda6"
# vbutil_kernel --repack $use_kernfs \
 --keyblock /usr/share/vboot/devkeys/kernel.keyblock \
 --version 1 \
 --signprivate /usr/share/vboot/devkeys/kernel_data_key.vbprivk \
 --oldblob $use_kernfs
# dd if=$use_kernfs of=${target_kern}

Finishing Up

  • Reboot and enjoy your Arch install! Note that ChrUbuntu's installer only told cgpt to boot to the Linux partition one time, so if anything is hosed, a reboot will send you back to ChromeOS. If all went well and you are happy with everything, you can reboot to ChromeOS, drop to the Ctrl+Alt+F2 console, and run a `sudo cgpt add -i 6 -P 5 -S 1 /dev/sda` to make the Chromebook always boot Arch.

Optional - Reducing Boot Times (DANGEROUS)

There is a way to silence the developer screen while reduce the auto boot time to three seconds(vs 30), removing the need to hit Ctrl+d each boot. This is dangerous because you can brick your Chromebook, requiring a JTAG to recover. These steps have been fully tested several times on several Acer C7 revisions. The BIOS flashing does not start if anything is unstable, having built in protection. Proceed with caution.

  • Make sure the battery is completely full, Acer C7 is plugged in, and booted into ChromeOS.
  • Press Ctrl+Alt+F2 or Ctrl+Alt+T to get to a terminal (log in if you use Ctrl+Alt+F2)
# cd ~/Downloads
# shell
# sudo -s
# flashrom -r bios.bin # Back up old BIOS
# gbb_utility –set –flags=0×01 bios.bin bios.new # Modifies the BIOS as needed
  • Refer to this image to find the "Write Protect Jumper" http://goo.gl/4OuGrw
  • Short the BIOS protect jumper, making sure the connection is stable. Jumpers from an old IDE HDD should work, I used a small knife.
# flashrom” again – “flashrom -w bios.new # Flashes the modified BIOS
  • If this command fails, the jumpers are not fully shorted or the connection became unstable on the jumpers. It will revert if the connection becomes unstable at any time. If it fails while in a flash, DO NOT REBOOT! Flash again until it works if it started the flash, ensuring tools recovery works and that you didn't have a bad flash. Do not rely on the built in check.
  • If successful, you should have a working BIOS mod. Reboot. The developer mode screen should vanish in three seconds, silently!
  • Back up bios.bin and bios.new to another machine or the cloud in case you ever want to revert.

See Also