ChromeOS device development begins with a Google-developed reference design. Partners then create unique implementations from that reference, which we refer to as “variants”.
The programs in this directory, plus some additional programs in private repositories, automate the process of creating the firmware source code for a new variant by copying and modifying source code from the reference design. After the base files are created, partners can customize the variant to their requirements by removing features which they do not want to offer (such as LTE), change parts (such as LPDDR3 memory instead of DDR4), or add other differentiating features.
Refer to the ChromeOS Partner Site for more details.
To create a new variant of a baseboard, you must be running inside the chroot environment. Please ensure that you have successfully synced your tree (repo sync) and that your toolchain is up-to-date (update_chroot). The programs create commits for the new and modified source files, and it is vital that these commits are based off cros/master.
new_variant.py runs the appropriate shell scripts in sequence and builds the code (via emerge) to verify that everything has been copied correctly. new_variant.py requires a --board and --variant parameter, and allows an optional --bug parameter, e.g.
$ ./new_variant.py --board=hatch --variant=sushi --bug=b:12345
to create the “sushi” variant of the “hatch” baseboard, and associate all of the commits with bug #12345 in Buganizer. If you omit the --bug parameter, the commit messages will include BUG=None.
new_variant.py supports the Hatch baseboad fully. Support for Volteer is in progress.
At a certain point in the program flow, new_variant.py may exit with a message that you need to run gen_fit_image.sh outside of the chroot; open a new terminal window, change to the appropriate directory, and run the script indicated. When it has finished, you can return to the chroot environment and run ./new_variant.py --continue to resume the program.
These programs are a work in progress. For any questions, problems, or suggestions, please contact chromeos-scale-taskforce@google.com.