diff --git a/workspace_tools/toolchains/__init__.py b/workspace_tools/toolchains/__init__.py
index daaa09c617..730fc50955 100644
--- a/workspace_tools/toolchains/__init__.py
+++ b/workspace_tools/toolchains/__init__.py
@@ -414,6 +414,10 @@ class mbedToolchain:
         for source in files_paths:
             if rel_path is not None:
                 relative_path = relpath(source, rel_path)
+            elif "RZ_A1H" in source and "iobitmasks" in source:
+                relative_path = source[source.rindex("iobitmasks"):]
+            elif "RZ_A1H" in source and "iodefines" in source:
+                relative_path = source[source.rindex("iodefines"):]
             else:
                 _, relative_path = split(source)