diff --git a/pkgs/misc/uboot/default.nix b/pkgs/misc/uboot/default.nix
index 262d976730f..60bf372b8db 100644
--- a/pkgs/misc/uboot/default.nix
+++ b/pkgs/misc/uboot/default.nix
@@ -1,5 +1,8 @@
 {stdenv, fetchurl, unzip, platform}:
 
+assert (stdenv.system != "i686-linux" && stdenv.system != "x86_64-linux")
+  || (stdenv ? cross);
+
 stdenv.mkDerivation {
   name = "uboot-2009.11";
    
diff --git a/pkgs/top-level/platforms.nix b/pkgs/top-level/platforms.nix
index 61ea4bafab2..492a0deaf12 100644
--- a/pkgs/top-level/platforms.nix
+++ b/pkgs/top-level/platforms.nix
@@ -8,8 +8,6 @@ with pkgs;
     # Build whatever possible as a module, if not stated in the extra config.
     kernelAutoModules = true;
     kernelTarget = "bzImage";
-    # This next line makes uboot happy, more than being ever used in the kernel build.
-    kernelArch = if (system == "i686-linux") then "x86" else "x86_64";
     kernelExtraConfig =
       ''
         # Virtualisation (KVM, Xen...).