You can make F6 do just one function by not using menuentry, just put in the command in the .cfg file - e.g.
reboot
and then when you press F6 it will reboot.
If you like to make your own menus, etc. you can try easy2boot ?
reboot
and then when you press F6 it will reboot.
If you like to make your own menus, etc. you can try easy2boot ?