From 2367007613f53172caedd0e958506b7f2fc3a36d Mon Sep 17 00:00:00 2001
From: matthewcroughan <matt@croughan.sh>
Date: Wed, 31 Aug 2022 14:10:09 +0100
Subject: [PATCH] nixos/modules/installer/cd-dvd/channel.nix: pin nixpkgs
 registry to pkgs.path via boot.postBootCommands

---
 nixos/modules/installer/cd-dvd/channel.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/nixos/modules/installer/cd-dvd/channel.nix b/nixos/modules/installer/cd-dvd/channel.nix
index 2f91cd39881d..159a9ca28c3e 100644
--- a/nixos/modules/installer/cd-dvd/channel.nix
+++ b/nixos/modules/installer/cd-dvd/channel.nix
@@ -45,6 +45,10 @@ in
         ln -s /nix/var/nix/profiles/per-user/root/channels /root/.nix-defexpr/channels
         mkdir -m 0755 -p /var/lib/nixos
         touch /var/lib/nixos/did-channel-init
+        echo "pinning the nixpkgs registry entry to NixOS/Nixpkgs sources..."
+        ${config.nix.package.out}/bin/nix \
+          --extra-experimental-features 'nix-command flakes' \
+          registry pin nixpkgs ${toString pkgs.path}
       fi
     '';
 }