diff --git a/docs/projectconf.rst b/docs/projectconf.rst
index 4783657c..abf14071 100644
--- a/docs/projectconf.rst
+++ b/docs/projectconf.rst
@@ -215,6 +215,12 @@ A protocol that "uploader" tool uses to talk to the board.
 A connection speed (`baud rate <http://en.wikipedia.org/wiki/Baud>`_)
 which "uploader" tool uses when sending firmware to board.
 
+``upload_flags``
+^^^^^^^^^^^^^^^^
+
+Extra flags for uploader. Will be added to the end of uploader command. If you
+need to override uploader command or base flags please use :ref:`projectconf_extra_script`.
+
 .. _projectconf_build_flags:
 
 ``build_flags``