diff --git a/modules/installer/cd-dvd/system-tarball-fuloong2f.nix b/modules/installer/cd-dvd/system-tarball-fuloong2f.nix
index 8ef112cc476..72b358f846d 100644
--- a/modules/installer/cd-dvd/system-tarball-fuloong2f.nix
+++ b/modules/installer/cd-dvd/system-tarball-fuloong2f.nix
@@ -147,6 +147,6 @@ in
   system.boot.loader.kernelFile = "/vmlinux";
 
   nixpkgs.config = {
-    platform = (import /etc/nixos/nixpkgs/pkgs/top-level/platforms.nix).fuloong2f_n32;
+    platform = pkgs.platforms.fuloong2f_n32;
   };
 }
diff --git a/modules/installer/cd-dvd/system-tarball-sheevaplug.nix b/modules/installer/cd-dvd/system-tarball-sheevaplug.nix
index b834ae3ab3d..745e756a0b4 100644
--- a/modules/installer/cd-dvd/system-tarball-sheevaplug.nix
+++ b/modules/installer/cd-dvd/system-tarball-sheevaplug.nix
@@ -183,8 +183,6 @@ in
   jobs.openssh.startOn = pkgs.lib.mkOverride 50 {} "";
 
   nixpkgs.config = {
-    packageOverrides = pkgs : rec {
-    };
-    platform = (import /etc/nixos/nixpkgs/pkgs/top-level/platforms.nix).sheevaplug;
+    platform = pkgs.platforms.sheevaplug;
   };
 }