PXE install NixOS - stage1 get of nix-root.squashfs issue

Hello all - very very new to NixOS. Trying to build a netboot installer via PXE of the 21.05 version, using the latest-nixos-minimal-x86_64-linux.iso build ISO.

My PXE infrastructure is working fine, and deploying other OSes. I"m looking to add NixOS support. So far, I am able to PXE boot the Stage 1 kernel / initrd … but I don’t know how to specify to get the nix-root.squashfs and do the appropriate preparation for the Stage 2 to load the init script:


I do know how to specify the init= ... piece, but the issue is the Store isn’t available from the initial Stage 1 kernel/initrd environment.

I’ve been digging around in the docs and various google searches, but so far haven’t been able to connect the dots.

Last question … is there such a thing as a “kickstart” or “preseed” configuration file to customize the Minimal ISO install environment?

Thank you in advance for any pointers or tips.