diff --git a/readme.md b/readme.md
index a41b7c3..62572e7 100644
--- a/readme.md
+++ b/readme.md
@@ -115,7 +115,9 @@ Put differently: it starts executing instructions at the address contained in `$
 - `1A   ` - pointer to display memory
 - `1B   ` - keypad: value of latest key pressed
 - `1C   ` - reserved for future use (bank switching flag)
-- `1D-FF` - free
+- `1D   ` - initial IP
+- `1D-FE` - free
+- `FF   ` - ROM (unwriteable) pointer to initial IP (not yet implemented)
 
 ## Peripherals