[Unit]
Description=custom configuration of live system during boot.
Before=basic.target
After=local-fs.target systemd-tmpfiles-setup.service
DefaultDependencies=no
ConditionKernelCommandLine=boot=live

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/local/bin/live-config

[Install]
WantedBy=basic.target