diff --git a/tools/config/__init__.py b/tools/config/__init__.py
index e1ad2be77d..9dc7ddc3d9 100644
--- a/tools/config/__init__.py
+++ b/tools/config/__init__.py
@@ -1124,10 +1124,14 @@ class Config(object):
         Config._check_required_parameters(params)
         params_with_values = [p for p in params.values() if p.value is not None]
         ctx = {
-            "cfg_params" : [(p.macro_name, str(p.value), p.set_by)
-                            for p in params_with_values],
-            "macros": [(m.macro_name, str(m.macro_value or ""), m.defined_by)
-                       for m in macros.values()],
+            "cfg_params": sorted([
+                (p.macro_name, str(p.value), p.set_by)
+                for p in params_with_values
+            ]),
+            "macros": sorted([
+                (m.macro_name, str(m.macro_value or ""), m.defined_by)
+                for m in macros.values()
+            ]),
             "name_len":  max([len(m.macro_name) for m in macros.values()] +
                              [len(m.macro_name) for m in params_with_values]
                              + [0]),
diff --git a/tools/toolchains/__init__.py b/tools/toolchains/__init__.py
index 3ff1f60e12..65dfcc928b 100644
--- a/tools/toolchains/__init__.py
+++ b/tools/toolchains/__init__.py
@@ -312,12 +312,17 @@ class mbedToolchain:
         """ Generate a via file for a pile of defines
         ARM, GCC, IAR cross compatible
         """
-        option_md5 = md5(' '.join(options).encode('utf-8')).hexdigest()
-        via_file = join(self.build_dir, naming.format(option_md5))
-        if not exists(via_file):
+        to_write = " ".join(options).encode('utf-8')
+        new_md5 = md5(to_write).hexdigest()
+        via_file = join(self.build_dir, naming.format(new_md5))
+        try:
+            with open(via_file, "r") as fd:
+                old_md5 = md5(fd.read().encode('utf-8')).hexdigest()
+        except IOError:
+            old_md5 = None
+        if old_md5 != new_md5:
             with open(via_file, "w") as fd:
-                string = " ".join(options)
-                fd.write(string)
+                fd.write(to_write)
         return via_file
 
     def get_inc_file(self, includes):