diff --git a/tools/buildbot-build.sh b/tools/buildbot-build.sh
index 3d70087..c1cc2e2 100755
--- a/tools/buildbot-build.sh
+++ b/tools/buildbot-build.sh
@@ -81,6 +81,8 @@
     # These targets are needed for the chroot environment.
     make_command+=" crash_dump event-log-tags"
   fi
+  # Build the Runtime APEX.
+  make_command+=" com.android.runtime"
   mode_suffix="-target"
 fi