diff --git a/pkgs/by-name/op/openscad-unstable/package.nix b/pkgs/by-name/op/openscad-unstable/package.nix
index 7f64438b8078..0184ab5753c6 100644
--- a/pkgs/by-name/op/openscad-unstable/package.nix
+++ b/pkgs/by-name/op/openscad-unstable/package.nix
@@ -44,33 +44,29 @@
   ctestCheckHook,
 }:
 # clang consume much less RAM than GCC
-clangStdenv.mkDerivation rec {
-  pname = "openscad-unstable";
-  version = "2025-06-04";
-  src = fetchFromGitHub {
-    owner = "openscad";
-    repo = "openscad";
-    rev = "65856c9330f8cc4ffcaccf03d91b4217f2eae28d";
-    hash = "sha256-jozcLFGVSfw8G12oSxHjqUyFtAfENgIByID+omk08mU=";
-    fetchSubmodules = true; # Only really need sanitizers-cmake and MCAD and manifold
-  };
-
-  patches = [ ./test.diff ];
-
-  # fix use of our lib3mf cmake export instead of finder
-  postPatch = ''
-    substituteInPlace CMakeLists.txt --replace-fail \
-      "Lib3MF" \
-      "lib3mf"
-  '';
-
-  nativeBuildInputs = [
-    (python3.withPackages (
+let
+  python3withPackages = (
+    python3.withPackages (
       ps: with ps; [
         numpy
         pillow
       ]
-    ))
+    )
+  );
+in
+clangStdenv.mkDerivation rec {
+  pname = "openscad-unstable";
+  version = "2021.01-unstable-2025-10-27";
+  src = fetchFromGitHub {
+    owner = "openscad";
+    repo = "openscad";
+    rev = "aa785fe4ab3d52450a5e51eb73585ac9bbcc8798";
+    hash = "sha256-TngfItArYtm8243DdYkQlkfc/MBTZGYrf08hfloWRWk=";
+    fetchSubmodules = true; # Only really need sanitizers-cmake and MCAD and manifold
+  };
+
+  nativeBuildInputs = [
+    python3withPackages
     bison
     cmake
     flex
@@ -134,6 +130,10 @@ clangStdenv.mkDerivation rec {
     # The sources enable this for only apple. We turn it off globally anyway to stay
     # consistent.
     "-DUSE_QT6=OFF"
+
+    # For tests
+    "-DVENV_DIR=${python3withPackages}"
+    "-DVENV_BIN_PATH=${python3withPackages}/bin"
   ];
 
   # tests rely on sysprof which is not available on darwin
@@ -147,6 +147,12 @@ clangStdenv.mkDerivation rec {
       done )
   '';
 
+  postPatch = ''
+    # Take Python3 executable as passed
+    sed -e '/set(VENV_DIR /d' -i tests/cmake/ImageCompare.cmake
+    sed -e '/find_path(VENV_BIN_PATH /d' -i tests/cmake/ImageCompare.cmake
+  '';
+
   postInstall = lib.optionalString stdenv.hostPlatform.isDarwin ''
     mkdir $out/Applications
     mv $out/bin/*.app $out/Applications
diff --git a/pkgs/by-name/op/openscad-unstable/test.diff b/pkgs/by-name/op/openscad-unstable/test.diff
deleted file mode 100644
index 23b3983daddd..000000000000
--- a/pkgs/by-name/op/openscad-unstable/test.diff
+++ /dev/null
@@ -1,42 +0,0 @@
-diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
-index 5c1b40af4..917451dee 100644
---- a/tests/CMakeLists.txt
-+++ b/tests/CMakeLists.txt
-@@ -59,13 +59,14 @@ if(USE_IMAGE_COMPARE_PY)
- 
-   # Since msys2 on Windows prefers bin/ over Scripts, we need to look for the actual folder to determine
-   # how to utilize the venv
--  find_path(VENV_BIN_PATH activate PATHS "${VENV_DIR}/bin" "${VENV_DIR}/Scripts" NO_DEFAULT_PATH NO_CACHE)
--  if(WIN32)
--    set(IMAGE_COMPARE_EXE "${VENV_BIN_PATH}/python.exe")
--  else()
--    set(IMAGE_COMPARE_EXE "${VENV_BIN_PATH}/python")
--  endif()
--  if(EXISTS "${IMAGE_COMPARE_EXE}")
-+  # find_path(VENV_BIN_PATH activate PATHS "${VENV_DIR}/bin" "${VENV_DIR}/Scripts" NO_DEFAULT_PATH NO_CACHE)
-+  # if(WIN32)
-+  #   set(IMAGE_COMPARE_EXE "${VENV_BIN_PATH}/python.exe")
-+  # else()
-+  #   set(IMAGE_COMPARE_EXE "${VENV_BIN_PATH}/python")
-+  # endif()
-+  set(IMAGE_COMPARE_EXE "python3")
-+  # if(EXISTS "${IMAGE_COMPARE_EXE}")
-     message(STATUS "venv found, testing libraries")
-     execute_process(
-       COMMAND "${IMAGE_COMPARE_EXE}" "${CCSD}/image_compare.py" "--status"
-@@ -77,10 +78,10 @@ if(USE_IMAGE_COMPARE_PY)
-       message(STATUS "venv libraries complete")
-       set(BUILD_VENV FALSE)
-     endif()
--  else()
--    message(STATUS "venv not found")
--    set(BUILD_VENV TRUE)
--  endif()
-+  # else()
-+  #   message(STATUS "venv not found")
-+  #   set(BUILD_VENV TRUE)
-+  # endif()
-   if(BUILD_VENV)
-     message(STATUS "Setting up testing venv for image comparison")
-     execute_process(
-