diff --git a/pkgs/development/python-modules/deal-solver/default.nix b/pkgs/development/python-modules/deal-solver/default.nix
index 2946db32d5af..9aff8a2c598c 100644
--- a/pkgs/development/python-modules/deal-solver/default.nix
+++ b/pkgs/development/python-modules/deal-solver/default.nix
@@ -45,6 +45,12 @@ buildPythonPackage rec {
 
   pythonImportsCheck = [ "deal_solver" ];
 
+  disabledTests = [
+    # Flaky tests, sometimes it works sometimes it doesn't
+    "test_expr_asserts_ok"
+    "test_fuzz_math_floats"
+  ];
+
   meta = with lib; {
     description = "Z3-powered solver (theorem prover) for deal";
     homepage = "https://github.com/life4/deal-solver";
diff --git a/pkgs/development/python-modules/pylddwrap/default.nix b/pkgs/development/python-modules/pylddwrap/default.nix
index cb68291f27e6..f4b4ea8ff7a5 100644
--- a/pkgs/development/python-modules/pylddwrap/default.nix
+++ b/pkgs/development/python-modules/pylddwrap/default.nix
@@ -7,18 +7,19 @@
   pytestCheckHook,
   pythonOlder,
   replaceVars,
+  setuptools,
   typing-extensions,
 }:
 
 buildPythonPackage rec {
   pname = "pylddwrap";
   version = "1.2.2";
-  format = "setuptools";
+  pyproject = true;
   disabled = pythonOlder "3.6";
 
   src = fetchFromGitHub {
     owner = "Parquery";
-    repo = pname;
+    repo = "pylddwrap";
     rev = "v${version}";
     hash = "sha256-Gm82VRu8GP52BohQzpMUJfh6q2tiUA2GJWOcG7ymGgg=";
   };
@@ -35,6 +36,8 @@ buildPythonPackage rec {
     rm -f $out/{LICENSE,README.rst,requirements.txt}
   '';
 
+  build-system = [ setuptools ];
+
   propagatedBuildInputs = [
     icontract
     typing-extensions