MP 1,1-5,1 nothing happens when attempting firmware update

[cinclodes]

I'm running the installer for High Sierra on a Mac Pro 5,1 that still has the original firmware. It says the firmware needs to be updated. When I click Shut Down as instructed, nothing happens. What might be the problem?

 

[cinclodes]

I got it to work by holding the power button.

 

[macguru9999]

You have to be booted off a drive in one of the bays, not a pcie