Skip to content

ian

De-Chroming the Acer c720 Chromebook

What is De-Chroming?

This talk is an instructional companion to the SFLC @ 10 Disposable Computing talk.

De-Chroming is the process of taking a Chromebook laptop, in this case the Acer c720, and replacing the Chrome operating system with a full-featured Debian install.

Why would you De-Chrome a laptop?

Perhaps you want access to all the great programs in Debian, perhaps you want a high security computer for use doing humanitarian work in hostile conditions, or perhaps you just want to tinker with some cool new hardware. There are many reasons you might be interested.

What do you need?

  • A small Philips-head screwdriver
  • A USB flash drive or an SD card with 100 megabytes free
  • A chromebook (this guide is for the Acer c720 model but other models are supported)
  • A wireless network

How to De-Chrome the c720 in 10 simple steps

This series of steps is designed to replace the default coreboot BIOS shipped on the laptop with a community-built version. This process brings a theoretical risk of bricking your device, which would require ~$50 of hardware and some technical knowledge to repair. You should be safe if you read all the instructions carefully but, if you would like to know more, take a look at the community wiki.

  1. Start the computer and log in to the chromebook guest account.
  2. Activate developer mode (note: this will delete all the user data on the machine so if you have been using the laptop you should back up your documents first).
  1. When you are logged in hold down Escape+Refresh(F3) and press the power button to reboot into recovery mode.
  2. Press Ctrl+D at the Recovery screen and then confirm that you would like to activate developer mode.
  1. Wait as it reboots and switches to developer mode, then shut down the machine.
  2. Remove write-protect screw as shown in: this video (available as mp4 or mkv).
  3. Reboot and re-log in as guest.
  4. Press Ctrl+Alt+t to get a Google terminal.
  5. In that terminal type “shell” to gain access to the full set of capabilities.
  6. Plug in your USB thumbdrive or insert your SD card.
  7. Run this command, which will download a script. (enter this as one unbroken line):

    cd; rm -f flash_chromebook_rom.sh; curl -k -L -O https://johnlewis.ie/flash_chromebook_rom.sh; sudo -E bash flash_chromebook_rom.sh

    Press 4 to backup your old BIOS and press 5 to install a community version from John Lewis.

  8. Once that has completed successfully and without errors, reboot. Now you can install Debian or your free software distribution of choice. If you received errors, do not reboot and seek help from the coreboot on chromebooks community.

Installing free software

Once you have replaced the default BIOS you will be able to boot from a USB device and install whatever version of a free software operating system you have handy. Everything on the c720 except for the bluetooth is supported with free software drivers so installation should be straightforward, though you may need to install the most recent kernel from your distribution to enable support for the trackpad. Some tips and tricks for dealing with any hardware issues you may run into are available from Kevin Keijzer’s blog on the FSFE site.

As with all of our SFLC machines, we install Debian and use the Debian installer to encrypt the hard drive. I am happy to report that that works perfectly well here whether you are installing to the internal drive or to an external USB thumb drive or SD card. That is important since, for most people, the only thing to consider when De-Chroming one of these laptops is what to do with the hard drive.

What to do with the hard drive

To keep costs down, Chromebooks are sold with hard drives that may be too small for most people to comfortably use as their only storage, generally 16 or 32 gigabytes. Those of us De-Chroming the laptops have a few general options for how to deal with this potential limitation: use it as is, replace the drive, or add extra storage with a USB drive or an SD card.

Use as is

16 GB is plenty of space for a Debian install, even using some for swap. This is especially true if you want to have your home partition on a separate thumb drive or SD card. This is also the cheapest and most straightforward option so, if cost is a factor or you just want to test out different versions of linux on the laptop, you should have plenty of space and can always expand it later.

Replace the drive

Larger SSDs are available for ~$50-60 online so if you want more space it is simple enough to just get a larger drive. Just make sure the disk you buy is compatible with the c720 laptop since there are a number of different format options available. There are only a couple dozen machines using these disks so far so any website selling them should list which ones are compatible. To replace the drive just open the case the same way you did to remove the write-protect screw and unscrew the one screw holding the drive in.

If I were going to use the laptop as my primary machine this is what I would do.

Expand the storage with USB or SD devices

Since the c720 has both a USB3 port and an SD card slot, it is easy enough to expand your available storage space with removable media. 64gb USB3 drives are available from $30-40 online. If you do not know how much space you will need, 64gb is probably enough space for you.

If you are buying a thumb drive you also have the opportunity to install the whole operating system to the thumb drive and leave no information about you on the laptop. This is particularly useful for people operating in high security situations like those doing humanitarian work in hostile countries, anyone who is worried about bringing a business machine back inside a secure facility, or anyone who is worried about having to decrypt a hard drive when crossing a hostile national boarder. With no information about you or your activities on the device, you can simply leave your laptop at whatever risky location you have traveled to and De-Chrome yourself a new one when you return to safer ground.

(Originally posted 2014-12-01 on the Software Freedom Law Center’s Blog)

Updated July 22, 2015 with options for updated script from John Lewis.

Information in this post may change over time. Check here for updates.

Technological Wizardry

The Washington Post editorial board just suggested that the tension between consumer’s right to encrypt their devices and the government’s legal power to access data with a search warrant could be resolved by magic.

Here is the final paragraph from Friday’s editorial Compromise needed on smartphone encryption:

How to resolve this? A police “back door” for all smartphones is undesirable — a back door can and will be exploited by bad guys, too. However, with all their wizardry, perhaps Apple and Google could invent a kind of secure golden key they would retain and use only when a court has approved a search warrant. Ultimately, Congress could act and force the issue, but we’d rather see it resolved in law enforcement collaboration with the manufacturers and in a way that protects all three of the forces at work: technology, privacy and rule of law.

They also seem to think that Congress could pass a law preventing us from using publicly available encryption technology on computers we own, which seems like a pretty big misunderstanding all be itself. Do you think they also want congress to mandate a secret unlock code for all physical safes sold in the US?

WikiConference USA

This past weekend was the inaugural WikiConference USA, a New York area conference focused on all things wiki. I presented a summary of our work with PS 9 at a session on Saturday morning and was privileged to share a track with Gabriel Thullen, a Swiss computer and media teacher who helps students contribute to Wikipedia as early as 7th grade. It was wonderful to see others who are working directly in schools and, as always, I was very pleased to talk with language teachers from as far away as San Francisco and Canada.

Every time I meet with people from the Wikipedia community I am struck by how strongly our goals for spreading knowledge and our values of openness, participation, and empowerment align. It is a welcome change of pace from stories about how technology is being used to surveil whole societies and how the tools of education are being used to build profiles of children. Now that we have reached the one year anniversary of Edward Snowden’s revelations I think we can all use a reminder that we can have a voice in how the technologies in our lives develop and whether they are used to support our values or undermine them. For myself, interacting with the other participants at WikiConference was that reminder.

Innovation in practice

In each Supreme Court brief that SFLC has filed over the years we have included a little note on the first page declaring that the brief was made using only free software. This point was particularly important in our most recent brief, for a case named Alice Corporation v. CLS Bank, which was argued in front of the court last week. Our use of free software was particularly important this time because we argue in our brief that free software has been responsible for the major software innovations of the modern era. In partial support of that claim I want to show you our document creation process and tell you about the free software we use to take text from an email and turn it into a camera-ready Supreme Court brief, then a website, then an eBook.

1: Markdown – the drafting tool

The first tool we use, markdown, is a standard way to use keyboard characters like *, #, and [ ] to indicate what parts of a text should be italicized or in bold and which parts are things like headers or footnotes. Using standard characters to indicate these formatting options helps keep the focus on the text and makes it possible to use a variety of collaboration tools during drafting like etherpad, wikis, and version control systems.

While we have all of those tools running at our office, and used many of them to share drafts of the brief, the initial versions of the CLS brief began as simple email messages. Markdown is a great tool for sharing documents via email because you can include the text of the message directly in the body of the message making it easy to make edits or add comments just by replying. Keeping the text of a document inside the email message also keeps every version track-able and search-able with your normal email tools. Contrast that to the common practice of sending documents around as attachments and how hard it is to identify which of the dozen files you may have is the first time a particular piece of text was introduced or a particular change was made.

2: Pandoc – the swiss army knife

Our second tool, pandoc, helps us translate the simple formatting and structure marks from our draft into whatever type of more formal document we need. When it comes to conversion, Pandoc is a swiss army knife that can turn our Markdown document into a webpage, word processor document, Wikipedia article, eBook, or many other formats. The format we want is LaTeX, which is a system for laying out complex documents that require precise formatting. It is commonly used for books, résumés, journal articles, dissertations, and, in our case, Supreme Court briefs.

To convert our “draft.mkdn” document to LaTeX we simply run “pandoc draft.mkdn -o draft.tex” which tells pandoc to look at the markdown file and output a LaTeX version of it. Since “.mkdn” and “.tex” are standard extensions for Markdown and LaTeX formatted documents, Pandoc understands the conversion we want it to do without any other instructions. For now that one command is all we want from pandoc but we will come back to it when building our eBook later on.

3: LaTeX, a personal print shop

Our third tool, LaTeX, is the software version of a professional print shop. It has everything you need to format and lay out documents down to the smallest printing measurement. This is different from a word processor in two important ways. The first is that LaTeX has a professional quality typesetting engine that calculates optimal spacing and line breaks. The result is simply beautiful documents. Take a look at this sample text printed as either a LibreOffice word processor document (pdf) or using the default LaTeX settings (pdf). Try printing that text with whatever tools you normally use and see which one you think is more attractive and pleasant to read.

The second important difference between LaTeX and a word processor is that LaTeX keeps the layout and document formatting information separate from the document contents. Importantly for us, this means we can do the complicated work of specifying all the Supreme Court’s detailed document requirements for briefs just once and then reuse that for each brief we file. We can even share that formatting file with you (brief.cls) so you can study how it works or use it for your own Supreme Court brief.

Once our draft text is in LaTeX format, which we get from pandoc, the final rounds of editing and polishing begin. This is the stage where we make sure that all the citations are correctly formatted and everything looks good on paper. For the CLS brief we made a couple tweaks, adding a page break before the last section so the last page would have more than two lines on it and deciding to indent the subheadings in the table of contents by adding a new option to the formatting “class” file.

When everything looks good, LaTeX creates a PDF that we can send directly to the printer for binding and delivery. Because all of the formatting work is done by LaTeX our document is “camera ready” which means we never have to worry about problems like using a different word processor version from the printer. As soon as the document leaves our hands we have complete confidence about how the document will look when printed. If there were any question about pdf compatibility LaTeX could even output a version in printer-native postscript format. As far as the court is concerned, our work is done once we send the file to be printed but we feel it is important to make the work we do as widely available as possible. To that end we try and share our publications in as many formats as possible that people might want. Our next two steps will take the same LaTeX file and turn it into a webpage and then an eBook.

4: Tex4ht

Turning a LaTeX file into a webpage is greatly helped by a tool called tex4ht which is an entire webpage layout engine built for LaTeX. The resulting website code can be a bit unorthodox when preserving some of the print features not used online, for instance small caps are created by formatting each letter separately and matching up the sizes, but it is very effective at transforming even complicated print documents into websites. It is the natural choice for something like a Supreme Court brief. You can see the results of running tex4ht on our final LaTeX brief at our site, which is basically unchanged from the default output of running “tex4ht alice-cls-amicus.tex” except for adding our standard website header and removing some extra dashes on the cover page.

5: Calibre

Transforming our LaTeX brief into an eBook begins with pandoc, the same tool we used to create our first LaTeX draft out of markdown. In addition to working with markdown, pandoc is able to convert to and from a number of other formats, including translating LaTeX into the “epub” eBook format. This is an important feature for us since, however careful our drafting efforts, some changes always creep in once our brief has moved out of markdown and into the review and proof reading passes. Pandoc’s ability to read as well as create LaTeX documents lets us focus on editing the document rather than worry about which format it is in during a particular editing step.

To get a rough version of the ebook we want we just run “pandoc alice-cls-amicus.tex -o Initial-eBook.epub” and pandoc will figure out what format we want from the file extensions. Because pandoc lacks some of the creative formatting tricks that tex4ht uses, like creating a word in small caps by formatting each letter separately, this initial eBook version is missing some of the elaborately formatted parts of the brief like the cover page.

Once we have this initial eBook we can polish up the rough edges using a free eBook library program called Calibre. Adding our draft to the Calibre library gives us access to a whole editing toolkit. Just select the book and hit the big “edit” button in the main toolbar. Since eBooks are basically websites, this final stage of processing is actually simple HTML editing. Conveniently, this means that we can replace the missing cover page by copying and pasting that portion from our website version. Since pandoc preserved all of the in-text formatting like italics and long dashes, all that is left to do is make sure that the sections and subsections all have appropriate HTML heading numbers, add in the spacing dots on the table of authorities, and tell Calibre to generate a table of contents.

This was actually my first time editing an eBook so that whole process tool me about an hour.

Conclusions

If you have only ever produced documents using commercial word processing software, many of the tools I have described here may seem strange to you. Like so much of Free and Open Source Software, the tools we use for making documents come from a variety of different authors who each produce documents their in own ways. The particular tools we use at SFLC have been chosen over the years as our practice grows and evolves. Whether you are looking to replace your document tools entirely, try out a new way to turn emailed text into word processor documents, or just see what it looks like to take free tools and put them together into a system that fits your office, I hope this has been an informative look at some innovative free software.

(Originally posted 2014-04-11 on the Software Freedom Law Center’s Blog)

Language exchange launch

Last night we began the second stage of the Last Language Textbook campaign at Brooklyn’s PS 9 elementary school. Fifteen parents and teachers gathered together to start a new language exchange organized around the materials that Wikiotics Fellows Claribel Sanchez and Jarrett Carter spent the summer building.

2013-11-18_194942-c-Wikiotics-LibraryShot

I am happy to report that everything went very well and the group is scheduled to meet again on December 2nd to continue learning basic Spanish vocabulary and practice their first English/Spanish dialogues. Any Spanish or English speaking parents in the community who would like to participate, please email contact@thelastlanguagetextbook.org. After December 2nd there will be a more formal schedule for the spring term meetings and we will post about it here.

css.php