Get Started Building EC Images (Quickly)

The Chromium OS Developer Guide and README walk through the steps needed to fetch and build Chromium OS source. These steps can be followed to retrieve and build EC source as well. On the other hand, if your sole interest is building an EC image, the general developer guide contains some extra unneeded steps.

The fastest possible way to build an EC image is to skip the Chromium OS chroot install entirely. The following steps have been tested on an Ubuntu 15.10 (Wily Werewolf) 64-bit host machine. Other distros / versions may be used, but toolchain incompatibilities may require extra debug.


  1. Install build / dev tools:

    sudo apt-get install git libftdi-dev libusb-dev libncurses5-dev gcc-arm-none-eabi
  2. Sync the cros-ec git repo:

    git clone
  3. Build your EC image:

    HOSTCC=x86_64-linux-gnu-gcc make BOARD=$board

External Dependencies

Most boards are buildable, but some will fail due to dependencies on external binaries (such as futility). Also, some related tools (such as flash_ec and servod) must be run from the Chromium OS chroot. Here is a set of steps to setup a minimal development environment to build EC images from the Chromium OS chroot:

  1. Create a folder for your chroot:

    mkdir cros-src; cd cros-src
  2. Run

    repo init -u --repo-url -g minilayout
  3. Edit .repo/manifest.xml, and add groups="minilayout" to the platform/ec project, so the line becomes:

    <project path="src/platform/ec" name="chromiumos/platform/ec" groups="minilayout" />
  4. Run repo sync:

    repo sync -j <number of cores on your workstatsion>
  5. Enter the chroot and enter your password for sudo if prompted:

  6. Set up your board:

    ./setup_board --board=$BOARD

    (ex. ./setup_board --board=glados)

  7. Build EC:

    ./build_packages --board=$BOARD chromeos-ec
  8. Now, EC images for any board can be built with:

    cd ~/trunk/src/platform/ec; make BOARD=$board -j

Building futility outside the chroot

If you want to build the futility host tool outside the normal Chrome OS chroot self-contained environment, you can try the following

  1. Install futility build dependencies:

    sudo apt-get install uuid-dev liblzma-dev libyaml-dev libssl-dev
  2. Get the vboot reference sources:

    git clone
  3. Build it:

    cd vboot_reference ; make
  4. Install it in /usr/local/bin:

    sudo make install
  5. Add /usr/local/bin to your default PATH:

    export PATH="${PATH}:/usr/local/bin"