diff --git a/README.md b/README.md
index 1cf1d36..2b55e38 100644
--- a/README.md
+++ b/README.md
@@ -12,4 +12,3 @@ Keyboard
 - F4: load program from tape (by simulating typing it)
 - F6: checkpoint machine
 - F7: restore from current checkpoint on tape
-- F8: enter debug mode (display current processor status on serial port)
diff --git a/apple1.ino b/apple1.ino
index e3eb8a8..6c1a753 100644
--- a/apple1.ino
+++ b/apple1.ino
@@ -84,9 +84,6 @@ void loop() {
 				if (filename)
 					restore(io.tape, PROGRAMS, filename);
 				break;
-			case PS2_F8:
-				cpu.debug();
-				break;
 			default:
 				io.up(key);
 				break;