diff --git a/README b/README
index 5f5655d..a48312a 100644
--- a/README
+++ b/README
@@ -77,6 +77,15 @@ More work remains to support all of libfdt, including access to numeric
 values.
 
 
+Adding a new function to libfdt.h
+---------------------------------
+
+The shared library uses libfdt/version.lds to list the exported functions, so
+add your new function there. Check that your function works with pylibfdt. If
+it cannot be supported, put the declaration in libfdt.h behind #ifndef SWIG so
+that swig ignores it.
+
+
 Tests
 -----