diff --git a/pkgs/os-specific/linux/zfs/generic.nix b/pkgs/os-specific/linux/zfs/generic.nix
index d27fe8511434..98d0236bcd90 100644
--- a/pkgs/os-specific/linux/zfs/generic.nix
+++ b/pkgs/os-specific/linux/zfs/generic.nix
@@ -221,11 +221,9 @@ let
           "--with-linux=${kernel.dev}/lib/modules/${kernel.modDirVersion}/source"
           "--with-linux-obj=${kernel.dev}/lib/modules/${kernel.modDirVersion}/build"
         ]
-        ++ kernelModuleMakeFlags
+        ++ map (f: "KERNEL_${f}") kernelModuleMakeFlags
       );
 
-      makeFlags = optionals buildKernel kernelModuleMakeFlags;
-
       enableParallelBuilding = true;
 
       doInstallCheck = true;