mchusandClaude Sonnet 4.6
e84c69d360
mkdir -p LOG_DIR before writing the optional step log so that a race with cleanup_build_log (EXIT trap archiving the log dir) does not cause a "Directory nonexistent" error during lb binary_checksums / lb binary_iso. Also downgrade apt-get update failure to a warning so a transient mirror outage does not block kernel ABI auto-detection when the apt cache is warm. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>