Summary: Use Windows PowerShell to find the firmware version of your virtual machines on Hyper-V.

 How can I use Windows PowerShell to check the version of firmware on my second-generation
          virtual machines running Hyper-V in Windows Server 2012 R2?

 Use the Get-VM cmdlet to find your second generation virtual machines,
          then pipe the virtual machine objects to the Get-VMFirmware cmdlet:

get-vm | where generation -eq 2 | Get-VMFirmware

Note  This command requires admin rights.