diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index 2e293f1031b0..11772dd7d555 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -1074,16 +1074,10 @@ self: super: {
   haddock-library = doJailbreak (dontCheck super.haddock-library);
   haddock-library_1_6_0 = doJailbreak (dontCheck super.haddock-library_1_6_0);
 
-  # cabal2nix requires hpack >= 0.29.6 but the LTS has hpack-0.28.2.
-  # Lets remove this once the LTS has upraded to 0.29.6.
-  hpack = super.hpack_0_29_7;
-
-  # The test suite does not know how to find the 'cabal2nix' binary.
-  cabal2nix = overrideCabal super.cabal2nix (drv: {
-    preCheck = ''
-      export PATH="$PWD/dist/build/cabal2nix:$PATH"
-      export HOME="$TMPDIR/home"
-    '';
+  # The tool needs a newer hpack version than the one mandated by LTS-12.x.
+  cabal2nix = super.cabal2nix.overrideScope (self: super: {
+    hpack = self.hpack_0_30_0;
+    yaml = self.yaml_0_10_1_1;
   });
 
   # Break out of "aeson <1.3, temporary <1.3".
diff --git a/pkgs/development/haskell-modules/hackage-packages.nix b/pkgs/development/haskell-modules/hackage-packages.nix
index dc2e2abed6ab..6fda57921886 100644
--- a/pkgs/development/haskell-modules/hackage-packages.nix
+++ b/pkgs/development/haskell-modules/hackage-packages.nix
@@ -41611,6 +41611,10 @@ self: {
          base Cabal containers directory filepath language-nix lens pretty
          process tasty tasty-golden
        ];
+       preCheck = ''
+         export PATH="$PWD/dist/build/cabal2nix:$PATH"
+         export HOME="$TMPDIR/home"
+       '';
        description = "Convert Cabal files into Nix build instructions";
        license = stdenv.lib.licenses.bsd3;
        maintainers = with stdenv.lib.maintainers; [ peti ];
@@ -202873,7 +202877,6 @@ self: {
        ];
        description = "Terminal emulator configurable in Haskell";
        license = stdenv.lib.licenses.bsd3;
-       hydraPlatforms = stdenv.lib.platforms.none;
      }) {gtk3 = pkgs.gnome3.gtk;};
 
   "termplot" = callPackage