even more tweaks

genfmts/isoplus.nix

@@ -1,4 +1,8 @@
-{ config, modulesPath, ... }: {
+{ config, lib, modulesPath, ... }:
+let
+  inherit (lib) mkDefault mkIf;
+  splash = config.boot.loader.grub.splashImage;
+in {
   imports = [
     "${modulesPath}/installer/cd-dvd/iso-image.nix"
     "${modulesPath}/profiles/all-hardware.nix"
@@ -12,13 +16,13 @@
   isoImage.appendToMenuLabel = "";
 
   # TODO: Persistent storage
-  lib.isoFileSystems."/" = {
+  lib.isoFileSystems."/home" = {
     device = "/iso/persistance";
-    options = [ "loop" ];
   };
 
-  swapDevices = [ ];
-  fileSystems = config.lib.isoFileSystems;
+  # Filesystems
+  swapDevices = mkDefault [ ];
+  fileSystems = mkDefault config.lib.isoFileSystems;
 
   # Prevent installation media from evacuating persistent storage, as their
   # var directory is not persistent and it would thus result in deletion of
@@ -29,9 +33,10 @@
   '';
 
   # Sync bootloader themes with general settings
+  # note: sync splashes, if not null
   isoImage.grubTheme = config.boot.loader.grub.theme;
-  isoImage.splashImage = config.boot.loader.grub.splashImage;
-  isoImage.efiSplashImage = config.boot.loader.grub.splashImage;
+  isoImage.splashImage = mkIf splash splash;
+  isoImage.efiSplashImage = mkIf splash splash;
 
   formatAttr = "isoImage";
   fileExtension = ".iso";