Replace fragile BSD sed append usage with awk when adding poststart chmods to the staged colibri_daemon rc.d script. The previous sed form appended the socket chmod after every line, corrupting the live USB service script.\n\nChecks: sh -n scripts/stage-colibri-iso.sh; fake COLIBRI_ARTIFACT_DIR staging; sh -n staged usr/local/etc/rc.d/colibri_daemon; git diff --check.
