diff --git a/README.md b/README.md
index 8413a0c..5f4fa05 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,7 @@ Enter setup mode.
 Copy boot.py to the root of the pico-ducky.  
 Copy your payload script to the pico-ducky.  
 Disconnect the pico from your host PC.
-Connect a jumper wire between pin 18 and pin 20.
+Connect a jumper wire between pin 18 (GND) and pin 20 (GPIO15).
 This will prevent the pico-ducky from showing up as a USB drive when plugged into the target computer.  
 Remove the jumper and reconnect to your PC to reprogram.
 The default mode is USB mass storage enabled.