Change boot order via WMI

I am looking to change the boot order of a load of 3080 SFFs by WMI (using PowerShell). 

Specifically, I would like to disable PXE over IPV6.

I have followed the advice in this whitepaper but it doesn't seem to work. I can't even swap round items in the boot order.

Has anyone had any success in disabling items in the boot order this way? Or even just changing the order?

Any help would be truly appreciated, as I don't want to change this on 100+ PCs.