SCVMM error : 23351 : The input string “” for the FirstBootDevice parameter cannot be parsed and may be invalid.

After importing an exported Generation 2 template in VMM, the following error occurs when trying to deploy :
The input string “” for the FirstBootDevice parameter cannot be parsed and may be invalid.
Make sure the string uses one of the following formats: “SCSI,BusId(integer),LunId(integer)” or “NIC,SlotId(integer)”
ID: 23351

This can be fixed up in Powershell like this :

Import-Module virtualmachinemanager
Get-SCVMTemplate -Name 'TEMPLATEXXX'  | Set-SCVMTemplate -FirstBootDevice 'SCSI,0,0'