silent BIOS upgrade

I want to silently upgrade my userbase's workstations but I don't want it to automatically reboot. Because this will be pushed remotely I can't just interrupt the users' work with a surprise reboot. 

Unfortunately I haven't found just using the /s works. I would figure that using /s would allow the BIOS upgrade to happen when the machine is rebooted by the user but that doesn't happen. The BIOS will only ever upgrade when /r is part of the deployment. 

Is there any way to do this?

Thanks