diff --git a/tools/buildman/README b/tools/buildman/README
index 0663ec3..fe76d4c 100644
--- a/tools/buildman/README
+++ b/tools/buildman/README
@@ -1125,7 +1125,7 @@
 If there are both warnings and errors, errors win, so buildman returns 128.
 
 The -y option is provided (for use with -s) to ignore the bountiful device-tree
-warnings.
+warnings. Similarly, -Y tells buildman to ignore the migration warnings.
 
 
 How to change from MAKEALL