diff --git a/variants/m5stack_coreink/variant.h b/variants/m5stack_coreink/variant.h
index 16f0bc6cf..ff9eda6f4 100644
--- a/variants/m5stack_coreink/variant.h
+++ b/variants/m5stack_coreink/variant.h
@@ -3,6 +3,7 @@
 
 //#define LED_PIN 10
 
+#include "pcf8563.h"
 // PCF8563 RTC Module
 #define PCF8563_RTC 0x51