two level if-else if-else. In such case case would be more readable:
```
startmode = case product_startmode
when "ifplugd"
  if replace_ifplugd?
    hotplug_usable ? "hotplug" : "auto"
  else
    product_startmode
  end
case "auto" then "auto"
else
   hotplug_usable ? "hotplug" : "auto"
end
```