diff --git a/hw/esp8266-pwm.h b/hw/esp8266-pwm.h
index 40967c2..de0eb4c 100644
--- a/hw/esp8266-pwm.h
+++ b/hw/esp8266-pwm.h
@@ -27,3 +27,5 @@
 #define PWM_SOUND	D2
 #define PWM_DUTY	20	// 20/1024 -> volume
 #define PWM_TOP		1024
+
+#define NO_CHECKPOINT	1