diff --git a/DOCS/tech/mpcf.txt b/DOCS/tech/mpcf.txt
index 6bd103a151..62a653ea8f 100644
--- a/DOCS/tech/mpcf.txt
+++ b/DOCS/tech/mpcf.txt
@@ -720,7 +720,8 @@ value
 
 stuffing
     0x80 can be placed in front of any type v entry for stuffing purposes
-
+    except the forward_ptr and all fields in the frame header where a
+    maximum of 8 stuffing bytes per field are allowed
 
 
 Structure: