diff --git a/docker_registry/app.py b/docker_registry/app.py
index 846fd2ec6..a4de07d10 100644
--- a/docker_registry/app.py
+++ b/docker_registry/app.py
@@ -27,9 +27,10 @@
 @app.route('/_ping')
 @app.route('/v1/_ping')
 def ping():
-    return toolkit.response(headers={
-        'X-Docker-Registry-Standalone': cfg.standalone is not False
-    })
+    headers = {'X-Docker-Registry-Standalone': cfg.standalone is not False}
+    if cfg.mirroring:
+        headers['X-Docker-Registry-Standalone'] = 'mirror'
+    return toolkit.response(headers=headers)
 
 
 @app.route('/')
diff --git a/docker_registry/lib/mirroring.py b/docker_registry/lib/mirroring.py
index e5160630c..daeb9fe0c 100644
--- a/docker_registry/lib/mirroring.py
+++ b/docker_registry/lib/mirroring.py
@@ -18,6 +18,18 @@ def is_mirror():
     return bool(cfg.get('mirroring', False))
 
 
+def _response_headers(base):
+    headers = {}
+    if not base:
+        return headers
+    for k, v in base.iteritems():
+        if k.lower() == 'content-encoding':
+            continue
+        headers[k.lower()] = v
+    logger.warn(headers)
+    return headers
+
+
 def lookup_source(path, stream=False, source=None):
     if not source:
         cfg = config.load()
@@ -77,10 +89,7 @@ def wrapper(namespace, repository, *args, **kwargs):
             if not source_resp:
                 return resp
 
-            headers = source_resp.headers
-            if 'Content-Encoding' in headers:
-                del headers['Content-Encoding']
-
+            headers = _response_headers(source_resp.headers)
             return toolkit.response(data=source_resp.content, headers=headers,
                                     raw=True)
 
@@ -105,10 +114,7 @@ def wrapper(namespace, repository, *args, **kwargs):
         if not source_resp:
             return resp
         data = source_resp.content
-        headers = source_resp.headers
-        if 'Content-Encoding' in headers:
-                del headers['Content-Encoding']
-
+        headers = _response_headers(source_resp.headers)
         cache.redis_conn.setex('{0}:{1}'.format(
             cache.cache_prefix, tag_path
         ), tags_cache_ttl, data)
@@ -142,11 +148,9 @@ def wrapper(*args, **kwargs):
 
             store = storage.load()
 
-            headers = source_resp.headers
-            if 'Content-Encoding' in headers:
-                del headers['Content-Encoding']
-            if index_route and 'X-Docker-Endpoints' in headers:
-                headers['X-Docker-Endpoints'] = toolkit.get_endpoints()
+            headers = _response_headers(source_resp.headers)
+            if index_route and 'x-docker-endpoints' in headers:
+                headers['x-docker-endpoints'] = toolkit.get_endpoints()
 
             if not stream:
                 logger.debug('JSON data found on source, writing response')
diff --git a/docker_registry/toolkit.py b/docker_registry/toolkit.py
index 6b7a2cf20..b1da0c219 100644
--- a/docker_registry/toolkit.py
+++ b/docker_registry/toolkit.py
@@ -48,14 +48,12 @@ def iterate(self, chunk_size=-1):
             if chunk_size == -1:
                 chunk_size = 1024
             for chunk in self._fp.iter_content(chunk_size):
-                logger.debug('Read %d bytes' % len(chunk))
                 for handler in self.handlers:
                     handler(chunk)
                 yield chunk
         else:
             chunk = self._fp.read(chunk_size)
             while chunk:
-                logger.debug('Read %d bytes' % len(chunk))
                 for handler in self.handlers:
                     handler(chunk)
                 yield chunk