diff --git a/tools/idf_py_actions/debug_ext.py b/tools/idf_py_actions/debug_ext.py
index 1140103f91..13c2c0397a 100644
--- a/tools/idf_py_actions/debug_ext.py
+++ b/tools/idf_py_actions/debug_ext.py
@@ -197,7 +197,7 @@ def action_extensions(base_actions: Dict, project_path: str) -> Dict:
             r.append('set confirm on')
             r.append('end')
             r.append('')
-            return os.linesep.join(r)
+            return '\n'.join(r)
         raise FatalError(f'{ESP_ROM_INFO_FILE} file not found. Please check IDF integrity.')
 
     def generate_gdbinit_files(gdb: str, gdbinit: Optional[str], project_desc: Dict[str, Any]) -> None: