diff --git a/litex/build/parser.py b/litex/build/parser.py
index 74359e2a9..ee2b4fb27 100644
--- a/litex/build/parser.py
+++ b/litex/build/parser.py
@@ -225,6 +225,13 @@ class LiteXArgumentParser(argparse.ArgumentParser):
         # Injects arguments default values
         if len(self._args_default):
             argparse.ArgumentParser.set_defaults(self, **self._args_default)
+            # Catch defaults which do not match any arguments - typos?
+            remaining = list(self._args_default.keys())
+            for action in self._actions:
+                if action.dest in remaining:
+                    remaining.remove(action.dest)
+            if len(remaining) > 0:
+                raise ValueError(f"set_default() for invalid argument(s): {remaining}")
 
         # Parse args.
         self._args = argparse.ArgumentParser.parse_args(self, args, namespace)