added grub theme

flake.nix

@@ -15,6 +15,7 @@
         windows-xp-theme = pkgs.callPackage ./windows-xp-theme.nix { };
         windows-xp-cursor = pkgs.callPackage ./windows-xp-cursor.nix { };
         windows-xp-plymouth = pkgs.callPackage ./windows-xp-plymouth.nix { };
+        windows-xp-grub = pkgs.callPackage ./windows-xp-grub.nix { };
         default = self.packages.${system}.windows-xp-theme;
     };
   };

windows-xp-grub.nix

@@ -0,0 +1,46 @@
+{
+  lib,
+  stdenvNoCC,
+  fetchFromGitHub,
+  nix-update-script,
+}:
+
+stdenvNoCC.mkDerivation {
+  pname = "grub-bios-theme";
+  version = "1.0";
+
+  src = fetchFromGitHub {
+    owner = "Blaysht";
+    repo = "grub_bios_theme";
+    rev = "main";
+    hash = "sha256-kYcEMCV9ipwPGgfAwOtFgYO4eHZxkUS97tOr0ft4rUE=";
+  };
+
+  dontBuild = true;
+
+  installPhase = ''
+    runHook preInstall
+
+    themeDir="$out/"
+    mkdir -p "$themeDir"
+
+    echo "Copying files from source root:"
+    ls -R .
+
+    # Copy all files safely
+    cp -r ./OldBIOS/* "$themeDir/"
+
+    runHook postInstall
+  '';
+
+  passthru.updateScript = nix-update-script { };
+
+  meta = {
+    description = "GRUB theme 'BIOS boot device' — minimalistic GRUB theme inspired by Vimix and primitivistical.";
+    homepage = "https://github.com/Blaysht/grub_bios_theme";
+    license = lib.licenses.mit;
+    maintainers = with lib.maintainers; [ azuwis ];
+    platforms = lib.platforms.linux;
+  };
+}
+

windows-xp-icons.nix

@@ -7,7 +7,7 @@
 }:
 
 stdenvNoCC.mkDerivation rec {
-  pname = "Windows-xp-icon-theme";
+  pname = "windows-xp-icon-theme";
   version = "2025-07-10";
 
   src = fetchFromGitHub {