diff --git a/m2-notes.txt b/m2-notes.txt
index f1058e1..44e5900 100644
--- a/m2-notes.txt
+++ b/m2-notes.txt
@@ -145,7 +145,9 @@ Window structure:
   0x28 - 0x29:  window height
   0x2A - 0x2B:  relative text X
   0x2C - 0x2D:  relative text Y
-  0x2E - 0x33:  ?
+  0x2E - 0x2F:  ?
+  0x30 - 0x31:  frame delay counter (counts down to 0, once per frame, after calling 1B FF xx xx)
+  0x32 - 0x33:  ?
   0x34 - 0x35:  cursor X
   0x36 - 0x37:  cursor Y
   0x38 - 0x43:  ?