nixos/stage-1-init: Set host id for ZFS

nixos/modules/tasks/network-interfaces.nix

@@ -403,6 +403,15 @@ let
     </itemizedlist>
   '';
 
+  hostidFile = pkgs.runCommand "gen-hostid" { preferLocalBuild = true; } ''
+      hi="${cfg.hostId}"
+      ${if pkgs.stdenv.isBigEndian then ''
+        echo -ne "\x''${hi:0:2}\x''${hi:2:2}\x''${hi:4:2}\x''${hi:6:2}" > $out
+      '' else ''
+        echo -ne "\x''${hi:6:2}\x''${hi:4:2}\x''${hi:2:2}\x''${hi:0:2}" > $out
+      ''}
+    '';
+
 in
 
 {
@@ -1383,16 +1392,8 @@ in
         domainname "${cfg.domain}"
       '';
 
-    environment.etc.hostid = mkIf (cfg.hostId != null)
-      { source = pkgs.runCommand "gen-hostid" { preferLocalBuild = true; } ''
-          hi="${cfg.hostId}"
-          ${if pkgs.stdenv.isBigEndian then ''
-            echo -ne "\x''${hi:0:2}\x''${hi:2:2}\x''${hi:4:2}\x''${hi:6:2}" > $out
-          '' else ''
-            echo -ne "\x''${hi:6:2}\x''${hi:4:2}\x''${hi:2:2}\x''${hi:0:2}" > $out
-          ''}
-        '';
-      };
+    environment.etc.hostid = mkIf (cfg.hostId != null) { source = hostidFile; };
+    boot.initrd.systemd.contents."/etc/hostid" = mkIf (cfg.hostId != null) { source = hostidFile; };
 
     # static hostname configuration needed for hostnamectl and the
     # org.freedesktop.hostname1 dbus service (both provided by systemd)