From 4c218190c317c74fb417bbf293f99fec23d7ed68 Mon Sep 17 00:00:00 2001
From: UGA Innovation Factory <engr-ugaif@uga.edu>
Date: Mon, 5 Jan 2026 12:16:51 -0500
Subject: [PATCH 1/2] fix: ensure system closure is installed for derivations
 needed by the installer

---
 installer/auto-install.nix | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/installer/auto-install.nix b/installer/auto-install.nix
index 68640cc..85c882c 100644
--- a/installer/auto-install.nix
+++ b/installer/auto-install.nix
@@ -53,14 +53,18 @@
       echo ">>> Running disko script..."
       ${diskoScript}
 
+      echo ">>> Copying system closure to target..."
+      # Copy the entire system closure without substitution
+      nix-store --store /mnt --load-db < <(nix-store --dump-db)
+      nix-copy-closure --to /mnt ${targetSystem} 2>/dev/null || true
+
       echo ">>> Running nixos-install..."
-      # Use only local store - don't fetch from binary cache or build
+      # Install with pre-built closure already in store
       nixos-install \
         --no-root-passwd \
         --root /mnt \
         --system ${targetSystem} \
-        --option substitute false \
-        --option build-use-sandbox false
+        --option substitute false
 
       echo ">>> Done. Rebooting."
       systemctl reboot

From b23525df7840d6e380ccd32d5cebabf2000b5d77 Mon Sep 17 00:00:00 2001
From: UGA Innovation Factory <engr-ugaif@uga.edu>
Date: Mon, 5 Jan 2026 12:29:32 -0500
Subject: [PATCH 2/2] fix: build closure in build-step instead of on iso

---
 installer/artifacts.nix    |  7 +++++++
 installer/auto-install.nix | 21 +++++++++++++--------
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/installer/artifacts.nix b/installer/artifacts.nix
index 087b1d1..c862a21 100644
--- a/installer/artifacts.nix
+++ b/installer/artifacts.nix
@@ -20,6 +20,12 @@ let
       targetConfig = self.nixosConfigurations.${hostName}.config;
       targetSystem = targetConfig.system.build.toplevel;
       diskoScript = targetConfig.system.build.diskoScript;
+      
+      # Build the closure export at build time (not runtime in ISO)
+      closureExport = pkgs.runCommand "closure-export-${hostName}" { } ''
+        mkdir -p $out
+        ${pkgs.nix}/bin/nix-store --export $(${pkgs.nix}/bin/nix-store -qR ${targetSystem}) > $out/closure.nar
+      '';
     in
     nixpkgs.lib.nixosSystem {
       inherit system;
@@ -29,6 +35,7 @@ let
           hostName
           targetSystem
           diskoScript
+          closureExport
           ;
         hostPlatform = system;
       };
diff --git a/installer/auto-install.nix b/installer/auto-install.nix
index 85c882c..63d0ef1 100644
--- a/installer/auto-install.nix
+++ b/installer/auto-install.nix
@@ -1,6 +1,7 @@
 # This module defines a systemd service that automatically installs NixOS to the disk.
 # It is intended to be used in an installation ISO.
-# It expects `targetSystem` (the closure to install) and `diskoScript` (the partitioning script) to be passed as arguments.
+# It expects `targetSystem` (the closure to install), `diskoScript` (the partitioning script),
+# and `closureExport` (the pre-built NAR archive) to be passed as arguments.
 {
   config,
   lib,
@@ -10,6 +11,7 @@
   hostPlatform,
   targetSystem,
   diskoScript,
+  closureExport,
   ...
 }:
 {
@@ -21,8 +23,12 @@
     targetSystem
   ];
 
-  # Explicitly include the system closure in the ISO image to prevent any need to build or fetch
+  # Explicitly include the pre-built closure export and system in the ISO image
   isoImage.contents = [
+    {
+      source = closureExport;
+      target = "/closure-export";
+    }
     {
       source = targetSystem;
       target = "/system";
@@ -53,14 +59,13 @@
       echo ">>> Running disko script..."
       ${diskoScript}
 
-      echo ">>> Copying system closure to target..."
-      # Copy the entire system closure without substitution
-      nix-store --store /mnt --load-db < <(nix-store --dump-db)
-      nix-copy-closure --to /mnt ${targetSystem} 2>/dev/null || true
+      echo ">>> Importing pre-built closure into target store..."
+      # Import the closure that was exported at build time
+      ${pkgs.nix}/bin/nix-store --store /mnt --import < /closure-export/closure.nar > /dev/null
 
       echo ">>> Running nixos-install..."
-      # Install with pre-built closure already in store
-      nixos-install \
+      # Install with pre-built closure already imported (no evaluation or fetching needed)
+      ${pkgs.nix}/bin/nixos-install \
         --no-root-passwd \
         --root /mnt \
         --system ${targetSystem} \