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Get Started Building EC Images (Quickly)

The Chromium OS Developer Guide and EC Development Guide 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 https://chromium.googlesource.com/chromiumos/platform/ec
  3. Build your EC image: HOSTCC=x86_64-linux-gnu-gcc make BOARD=$board

Most boards are buildable, but some will fail due to dependencies on external binaries (such as futility [1]). 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 (ex. mkdir cros-src; cd cros-src)
  2. Run repo init https://chromium.googlesource.com/chromiumos/manifest.git -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. repo sync -j <number of cores on your workstatsion>
  5. ./chromite/bin/cros_sdk and enter your password for sudo if prompted
  6. cros build-packages --board=$BOARD chromeos-ec
  7. Now, EC images for any board can be built with cd ~/chromiumos/src/platform/ec; make BOARD=$board -j

[1] 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 https://chromium.googlesource.com/chromiumos/platform/vboot_reference
  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"