With the release of Parallels Desktop 19.3 a warning of future functionality deprecation was announced including: Network boot for macOS virtual machines . I have found Parallels Desktop extremely useful for testing NetInstall services and it is possible to continue in a different way:
- Download an ISO is available from: https://github.com/windli2018/virtualbox-efi-netboot
- Attach the ISO to the virtual machine as a CD/DVD
- Set the Boot Order to include CD/DVD. If no operating system is installed on the hard disk you can leave the Boot order as it is, or you can check “Select boot device on startup” for more control.
The VirtualBox EFI NetBoot ISO can work with other virtualisation solutions, and potentially physical hardware. Should the readily available ISO not work a script is available to build a new one.