$ mkdir ~/cesium
$ cd ~/cesium
$ repo init -u https://github.com/CesiumOS-org/manifest.git -b tiramisu-rel
[Hint: This might take a long time as the source is ~70GB]
$ repo sync -c -j$(nproc --all) --force-sync --no-clone-bundle --no-tags
$ cd ~/cesium
$ source build/envsetup.sh
$ lunch <devicecodename>-user
$ m bacon | tee build.log