diff --git a/src/include/pc80/mc146818rtc.h b/src/include/pc80/mc146818rtc.h
index b0e9f2c..fd40308 100644
--- a/src/include/pc80/mc146818rtc.h
+++ b/src/include/pc80/mc146818rtc.h
@@ -217,6 +217,8 @@
 #define CMOS_POST_BANK_1_OFFSET   (CMOS_POST_OFFSET + 2)
 #define CMOS_POST_BANK_1_EXTRA    (CMOS_POST_OFFSET + 7)
 
+#define CMOS_POST_EXTRA_DEV_PATH  0x01
+
 void cmos_post_log(void);
 #endif /* CONFIG_CMOS_POST */