diff --git a/pmca/installer/__init__.py b/pmca/installer/__init__.py
index d26716e..3d8b78a 100644
--- a/pmca/installer/__init__.py
+++ b/pmca/installer/__init__.py
@@ -15,7 +15,7 @@
 Result = namedtuple('Result', 'code, message')
 
 def _buildRequest(endpoint, contentType, data):
- return b'POST %s REST/1.0\r\nContent-type: %s\r\n\r\n%s' % (endpoint.encode('latin1'), contentType.encode('latin1'), data)
+ return b'POST ' + endpoint.encode('latin1') + b' REST/1.0\r\nContent-type: ' + contentType.encode('latin1') + b'\r\n\r\n' + data
 
 def _parseHttp(data):
  headers, data = data.split(b'\r\n\r\n')[:2]
diff --git a/pmca/util/http.py b/pmca/util/http.py
index 70d35fd..9eb23fe 100644
--- a/pmca/util/http.py
+++ b/pmca/util/http.py
@@ -24,11 +24,11 @@ def postFile(url, fileName, fileData, fieldName='', headers={}, cookies={}, auth
  boundary = ''.join(random.choice('-_' + string.digits + string.ascii_letters) for _ in range(40))
  headers['Content-type'] = 'multipart/form-data; boundary=%s' % boundary
  data = b'\r\n'.join([
-  b'--%s' % boundary.encode('latin1'),
-  b'Content-Disposition: form-data; name="%s"; filename="%s"' % (fieldName.encode('latin1'), fileName.encode('latin1')),
+  b'--' + boundary.encode('latin1'),
+  b'Content-Disposition: form-data; name="' + fieldName.encode('latin1') + b'"; filename="' + fileName.encode('latin1') + b'"',
   b'',
   fileData,
-  b'--%s--' % boundary.encode('latin1'),
+  b'--' + boundary.encode('latin1') + b'--',
   b'',
  ])
  return request(url, data, headers, cookies, auth)