When the bootoption "startx" is given, the helper-script
"/etc/init.d/startx" is created during the bootprocess (via
grml-autoconfig).
That means, that if the booptions "startx" is not given, the
helper-script is not created and tty6/vt6 should not try to start X but
should just start a grml-user-shell.
Related to grml/grml#20
[Service]
Type=idle
ExecStart=
-ExecStart=-/bin/zsh --login -c "[ ! -e /var/run/grml_startx.started ] && (touch /var/run/grml_startx.started && /sbin/grml-runtty /dev/tty6 /etc/init.d/startx root; chvt 1) || /sbin/grml-runtty /dev/tty6 /bin/zsh $USERNAME" >/dev/tty6 2>&1 < /dev/tty6
+ExecStart=-/bin/zsh --login -c "[ ! -e /var/run/grml_startx.started ] && [ -x /etc/init.d/startx ] && (touch /var/run/grml_startx.started && /sbin/grml-runtty /dev/tty6 /etc/init.d/startx root; chvt 1) || /sbin/grml-runtty /dev/tty6 /bin/zsh $USERNAME" >/dev/tty6 2>&1 < /dev/tty6