If you need the full power of a desktop OS, you can boot a Chromebook with both Chrome OS and Ubuntu. Darien Graham-Smith explains how.
Google’s Chromebook concept has gained momentum lately. When it was unveiled in mid-2011, the idea of a system in which everything happened in the browser was met with distrust: how would we get by without our familiar desktop applications? And how would anything work on the go? Successive updates to the OS, with richer apps and offline support, have to an extent quelled these concerns, while hardware prices have fallen to tempting lows.
Yet the system is still limited compared to a regular laptop. The browser-based model is good for simplicity and security, but most existing applications, games and development tools don’t run in the cloud, and many probably never will. Although hardly in the spirit of the Chromebook concept, there’s no denying that the option of booting into a regular desktop OS adds considerably to its flexibility.
Google doesn’t advertise the fact, but such a feat is perfectly possible. Almost all Chromebooks are based on standard Intel Atom or Celeron processors, so there’s no fundamental obstacle to setting up a dual-boot system offering a mainstream Linux distribution alongside Chrome OS.
It isn’t quite as easy as simply plugging in a USB drive and launching the installer, however. Chromebooks are locked down in a way that doesn’t allow you to boot operating systems or external bootloaders other than Chrome OS.
Much like Windows 8’s Secure Boot feature, this ensures a rogue rootkit can’t take over your system by tricking the BIOS into booting it before the OS starts up. It also means, if you want to install a secondary operating system, you’ll need to delve into the Chromebook’s developer settings and install the guest operating system via the command line.
Does this sound daunting? Don’t panic. A helpful hacker named Jay Lee has done almost all the work for you, creating an online script that will automatically download and install Ubuntu Linux 12.04 onto your Chromebook – an installation that can then be upgraded to the latest 12.10 release and, in time, beyond. The project website, with the latest updates and discussions, can be found at http://chromeos-cr48.blogspot.co.uk/.
On these pages, we’ll show you how to use the script, and give you a few pointers to help you get the best from Ubuntu on your Chromebook.
Generally speaking, Ubuntu runs well on an Atom-based Chromebook. Performance is inevitably rather slow – this is a netbook CPU we’re using, after all – but all the hardware works, and you should be able to download and install updates and applications without problems. Before you jump into the process of installing it, however, there are a few Chromebook-specific niggles to bear in mind.
First, because of the way the Chromebook BIOS is locked down, you’ll have to keep your laptop in developer mode in order to use Ubuntu. This isn’t exactly a problem, but it does mean you’ll have to dismiss a warning screen (or wait 30 seconds for it to close) every time you power on the system. And if anyone does, at some point, come up with a rootkit exploit for Chromebooks, you’ll be vulnerable.
It’s also worth noting there’s no boot menu: if you want to switch from one OS to the other, you’ll have to reconfigure your boot settings at the command line then restart the machine.
Since Chromebooks naturally have no Windows key to serve as the “Super” modifier, some standard Ubuntu shortcuts won’t work (notably, the one for opening the Dash search interface). You may, therefore, want to open up the Keyboard Layout and Shortcut options and assign your own shortcuts to frequently accessed functions. You’ll also have to get used to using function keys with shortcut symbols on them, rather than numbers.
We’re sure you’ll agree, however, that these irritations are a small price to pay for the whole new dimension of usefulness that Ubuntu brings to the Chromebook.
Entering developer mode
As we mentioned earlier, Chromebook systems are heavily locked down – but don’t let that put you off. Google states openly that the various protections built into the system are there solely to thwart malware, not to prevent users from experimenting with their own systems. If you want to repartition your hard disk and configure the system to boot into a different OS, you can gain the required permissions by simply switching the Chromebook into developer mode.
Be warned that entering developer mode causes all the data cached on your Chromebook to be automatically wiped. This shouldn’t inconvenience you, since all your data and settings will normally be stored safely in the cloud – it’s just a security measure to prevent someone who doesn’t know your Chrome OS password from booting into a different OS to snoop at your files. If you’ve been working offline, however, it’s worth making sure everything is synced before you switch modes.
How you move the switch to developer mode depends on your particular model of Chromebook. On Samsung models, it’s done via a switch at the right-hand side of the chassis. On the Acer AC700, the switch is underneath the battery. If you’re using an Acer C7, you enable developer mode by holding down the Escape and Refresh keys while powering on the system, then pressing Ctrl-D to reboot into developer mode.
As long as you’re in developer mode, your Chromebook will start up with a screen warning that “OS verification is turned off”. This screen can’t be disabled: it’s there so you can’t be tricked into running an unauthorised operating system without realising it.
If you press the spacebar from this screen, you’ll be taken to the recovery interface, from where you can reinstall Chrome OS. Press Ctrl-D instead (or wait 30 seconds) and the Chrome OS initial setup window will then appear, asking you to choose language and networking options.
If you’re using an Acer C7 or a Samsung Series 5 550, you can now skip to the next section. For the original Samsung Series 5 and Acer AC700, there’s one more step to take, since these devices have an additional layer of BIOS protection that must be disabled.
This is done from the command line. To access it, hold down Ctrl-Alt and press the Forward Arrow key (that is, the navigation key in the F2 position along the top of the keyboard). At the login prompt, give your username as “chronos”; you shouldn’t be asked for a password but rather presented with a command line. Enter these two lines:
Once the BIOS mode has been changed, reboot the Chromebook. At the warning, press Ctrl-D once again to access the setup window.