diff --git a/tools/toolchains/__init__.py b/tools/toolchains/__init__.py
index 3da97efe00e..dac095a8162 100644
--- a/tools/toolchains/__init__.py
+++ b/tools/toolchains/__init__.py
@@ -147,8 +147,7 @@ def relative_to(self, base, dot=False):
             v = [rel_path(f, base, dot) for f in getattr(self, field)]
             setattr(self, field, v)
 
-        for f in self.features:
-            self.features[f] = rel_path(self.features[f], base, dot)
+        self.features = {k: f.relative_to(base, dot) for k, f in self.features.iteritems()}
 
         if self.linker_script is not None:
             self.linker_script = rel_path(self.linker_script, base, dot)
@@ -161,8 +160,7 @@ def win_to_unix(self):
             v = [f.replace('\\', '/') for f in getattr(self, field)]
             setattr(self, field, v)
 
-        for f in self.features:
-            self.features[f] = self.features[f].replace('\\', '/')
+        self.features = {k: f.win_to_unix() for k, f in self.features.iteritems()}
 
         if self.linker_script is not None:
             self.linker_script = self.linker_script.replace('\\', '/')