diff --git a/pkgs/applications/science/logic/mcy/default.nix b/pkgs/applications/science/logic/mcy/default.nix
index 343b50dfd7ef..65c752f62999 100644
--- a/pkgs/applications/science/logic/mcy/default.nix
+++ b/pkgs/applications/science/logic/mcy/default.nix
@@ -32,7 +32,7 @@ stdenv.mkDerivation {
   '';
 
   # the build needs a bit of work...
-  buildPhase = "true";
+  dontBuild = true;
   installPhase = ''
     mkdir -p $out/bin $out/share/mcy/{dash,scripts}
     install mcy.py      $out/bin/mcy      && chmod +x $out/bin/mcy
diff --git a/pkgs/applications/science/robotics/sumorobot-manager/default.nix b/pkgs/applications/science/robotics/sumorobot-manager/default.nix
index eb9322f0fb22..a26bd5d5fc28 100644
--- a/pkgs/applications/science/robotics/sumorobot-manager/default.nix
+++ b/pkgs/applications/science/robotics/sumorobot-manager/default.nix
@@ -18,7 +18,7 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ wrapPython qt5.wrapQtAppsHook dos2unix ];
 
-  buildPhase = "true";
+  dontBuild = true;
 
   installPhase = ''
     mkdir -p $out/opt/sumorobot-manager
diff --git a/pkgs/data/themes/numix-solarized/default.nix b/pkgs/data/themes/numix-solarized/default.nix
index af06075de7d3..55e606e6a0a9 100644
--- a/pkgs/data/themes/numix-solarized/default.nix
+++ b/pkgs/data/themes/numix-solarized/default.nix
@@ -20,7 +20,7 @@ stdenv.mkDerivation rec {
     substituteInPlace Makefile --replace '$(DESTDIR)'/usr $out
   '';
 
-  buildPhase = "true";
+  dontBuild = true;
 
   installPhase = ''
     runHook preInstall
diff --git a/pkgs/development/libraries/science/math/rubiks/default.nix b/pkgs/development/libraries/science/math/rubiks/default.nix
index 8f3fbe345126..a3fba32d05c3 100644
--- a/pkgs/development/libraries/science/math/rubiks/default.nix
+++ b/pkgs/development/libraries/science/math/rubiks/default.nix
@@ -19,7 +19,7 @@ stdenv.mkDerivation rec {
   '';
 
   # everything is done in `make install`
-  buildPhase = "true";
+  dontBuild = true;
 
   installFlags = [
     "PREFIX=$(out)"
diff --git a/pkgs/games/ckan/default.nix b/pkgs/games/ckan/default.nix
index ed025ecee5d6..e96adbf69d06 100644
--- a/pkgs/games/ckan/default.nix
+++ b/pkgs/games/ckan/default.nix
@@ -16,7 +16,7 @@ stdenv.mkDerivation rec {
 
   libraries = lib.makeLibraryPath [ gtk2 curl ];
 
-  buildPhase = "true";
+  dontBuild = true;
 
   installPhase = ''
     install -m 644 -D $src $out/bin/ckan.exe
diff --git a/pkgs/tools/archivers/unp/default.nix b/pkgs/tools/archivers/unp/default.nix
index 247f393226d7..c11a21d05968 100644
--- a/pkgs/tools/archivers/unp/default.nix
+++ b/pkgs/tools/archivers/unp/default.nix
@@ -20,7 +20,7 @@ in stdenv.mkDerivation {
   };
 
   dontConfigure = true;
-  buildPhase = "true";
+  dontBuild = true;
   installPhase = ''
   mkdir -p $out/bin
   mkdir -p $out/share/man/man1