diff --git a/pkgs/by-name/ki/kissfft/package.nix b/pkgs/by-name/ki/kissfft/package.nix
index 03d0e7d04584..985ecb761996 100644
--- a/pkgs/by-name/ki/kissfft/package.nix
+++ b/pkgs/by-name/ki/kissfft/package.nix
@@ -57,7 +57,7 @@ stdenv.mkDerivation (finalAttrs: {
     (lib.cmakeFeature "KISSFFT_DATATYPE" datatype)
     (lib.cmakeBool "KISSFFT_STATIC" enableStatic)
     # `test/testkiss.py` expects this…
-    (lib.cmakeFeature "KISSFFT_OPENMP" (if enableOpenmp then "ON" else "OFF"))
+    (lib.cmakeBool "KISSFFT_OPENMP" enableOpenmp)
   ];
 
   # Required for `test/testcpp.c`.
diff --git a/pkgs/by-name/va/vanillatd/package.nix b/pkgs/by-name/va/vanillatd/package.nix
index 3864e687d3cf..4b17a2527e1a 100644
--- a/pkgs/by-name/va/vanillatd/package.nix
+++ b/pkgs/by-name/va/vanillatd/package.nix
@@ -66,10 +66,10 @@ stdenv.mkDerivation (finalAttrs: {
     ];
 
   cmakeFlags = [
-    (lib.cmakeFeature "BUILD_VANILLATD" (if appName == "vanillatd" then "ON" else "OFF"))
-    (lib.cmakeFeature "BUILD_VANILLARA" (if appName == "vanillara" then "ON" else "OFF"))
-    (lib.cmakeFeature "BUILD_REMASTERTD" (if appName == "remastertd" then "ON" else "OFF"))
-    (lib.cmakeFeature "BUILD_REMASTERRA" (if appName == "remasterra" then "ON" else "OFF"))
+    (lib.cmakeBool "BUILD_VANILLATD" (appName == "vanillatd"))
+    (lib.cmakeBool "BUILD_VANILLARA" (appName == "vanillara"))
+    (lib.cmakeBool "BUILD_REMASTERTD" (appName == "remastertd"))
+    (lib.cmakeBool "BUILD_REMASTERRA" (appName == "remasterra"))
     (lib.cmakeFeature "CMAKE_BUILD_TYPE" CMAKE_BUILD_TYPE)
   ];