Unable to create Hyper-V private router with downloaded VHD disk

I wish to create a “generation 2” Hyper-V private router because my machine boots with UEFI and so “generation 1” VM with VHD format disk is not possible. I was able to convert the downloaded VHD disk file with Hyper-V manager. I did these steps:

  1. Actions > Edit Disk
  2. Pick the VHD file and “convert”
  3. When finished now create a new Gen2 machine and choose existing VHDX disk
  4. You must disable secure boot for Windows to allow Linux OS

@edwardm Could please have a look at this query?