diff --git a/datasketches/tests/countmin_serialization_test.rs b/datasketches/tests/countmin_serialization_test.rs
index 4492a55..6c2c5a5 100644
--- a/datasketches/tests/countmin_serialization_test.rs
+++ b/datasketches/tests/countmin_serialization_test.rs
@@ -53,17 +53,17 @@ fn assert_cpp_snapshot(
 
 #[test]
 fn test_deserialize_cpp_empty_snapshot() {
-    assert_cpp_snapshot("count_min-empty.bin", 9001, 1, 5, 0);
+    assert_cpp_snapshot("count_min_empty_cpp.sk", 9001, 1, 5, 0);
 }
 
 #[test]
 fn test_deserialize_cpp_non_empty_snapshot() {
-    assert_cpp_snapshot("count_min-non-empty.bin", 9001, 3, 1024, 2850);
+    assert_cpp_snapshot("count_min_non_empty_cpp.sk", 9001, 3, 1024, 2850);
 }
 
 #[test]
 fn test_deserialize_cpp_snapshot_with_wrong_seed() {
-    let path = serialization_test_data("cpp_generated_files", "count_min-non-empty.bin");
+    let path = serialization_test_data("cpp_generated_files", "count_min_non_empty_cpp.sk");
     let bytes = fs::read(&path).unwrap();
 
     let err = CountMinSketch::<u64>::deserialize_with_seed(&bytes, 9000).unwrap_err();
diff --git a/tools/generate_serialization_test_data.py b/tools/generate_serialization_test_data.py
index 28314b1..3bc9e8d 100755
--- a/tools/generate_serialization_test_data.py
+++ b/tools/generate_serialization_test_data.py
@@ -71,7 +71,7 @@ def generate_java_files(workspace_dir, project_dir):
 
     # 4. Clone repository
     repo_url = "https://github.com/apache/datasketches-java.git"
-    branch = "9.0.0" # FIXME: temporarily use fixed branch until mvn issue is resolved
+    branch = "9.0.0"
     run_command([
         "git", "clone",
         "--depth", "1",
@@ -133,21 +133,15 @@ def generate_cpp_files(workspace_dir, project_root):
 
     # 4. Clone repository
     repo_url = "https://github.com/apache/datasketches-cpp.git"
-    branch = "master"
-    # Temporary e2e checkout for apache/datasketches-cpp#505. After that PR is
-    # merged, pin this to the merged master commit and remove the extra fetch.
-    commit = "af4436280bdab53e0063268e92ff29b3fdcb1b07"
-    fetch_ref = "refs/pull/505/head"
+    commit = "401423367055acdf7502e8ed3126730a08039d91"
     run_command([
         "git", "clone",
         "--depth", "1",
-        "--branch", branch,
+        "--revision", commit,
         "--single-branch",
         repo_url,
         str(temp_dir)
     ])
-    run_command(["git", "fetch", "--depth", "1", "origin", fetch_ref], cwd=temp_dir)
-    run_command(["git", "checkout", "--detach", commit], cwd=temp_dir)
 
     # 5. Build and Run CMake
     build_dir = temp_dir / "build"
@@ -173,14 +167,14 @@ def generate_cpp_files(workspace_dir, project_root):
 
     files_copied = 0
 
-    for pattern in ("*_cpp.sk", "count_min-*.bin"):
-        for file_path in build_dir.rglob(pattern):
-            shutil.copy2(file_path, output_dir)
-            print(f"Copied: {file_path.name}")
-            files_copied += 1
+    for file_path in build_dir.rglob("*_cpp.sk"):
+        shutil.copy2(file_path, output_dir)
+        print(f"Copied: {file_path.name}")
+        files_copied += 1
+
 
     if files_copied == 0:
-        print("Warning: No C++ serialization snapshots were found to copy.")
+        print("Warning: No *_cpp.sk files were found to copy.")
     else:
         print(f"Successfully copied {files_copied} files.")