diff --git a/tools/export/iar.py b/tools/export/iar.py
index 6323563b64..f977933f51 100644
--- a/tools/export/iar.py
+++ b/tools/export/iar.py
@@ -67,8 +67,9 @@ class IAREmbeddedWorkbench(Exporter):
 
         project_data['tool_specific'] = {}
         project_data['tool_specific'].setdefault("iar", {})
-        project_data['tool_specific']['iar'].update(self.progen_flags)
-        project_data['tool_specific'].update(tool_specific)
+        project_data['tool_specific']['iar'].setdefault("misc", {})
+        project_data['tool_specific']['iar'].update(tool_specific['iar'])
+        project_data['tool_specific']['iar']['misc'].update(self.progen_flags)
         project_data['common']['build_dir'] = os.path.join(project_data['common']['build_dir'], 'iar_arm')
         self.progen_gen_file('iar_arm', project_data)