diff --git a/notes/todo.md b/notes/todo.md
index b8e2f35..a2b9df8 100644
--- a/notes/todo.md
+++ b/notes/todo.md
@@ -1,5 +1,7 @@
 # To do
 
+- [ ] Figure out why $00 contains $20
+
 ## Research
 
 - [ ] Review CHIP-8