[Unit]
Description=Save initial kernel messages after boot

[Service]
Type=idle
StandardOutput=file:/var/log/dmesg
ExecStartPre=-/usr/bin/savelog -q -p -n -c 5 /var/log/dmesg
ExecStart=/bin/journalctl --boot 0 --dmesg --output short-monotonic --quiet --no-pager --no-hostname
ExecStartPost=/bin/chgrp adm /var/log/dmesg

[Install]
WantedBy=multi-user.target