diff --git a/sys/dev/isp/ispmbox.h b/sys/dev/isp/ispmbox.h
index 8dcef10fc820..5fee105d32f1 100644
--- a/sys/dev/isp/ispmbox.h
+++ b/sys/dev/isp/ispmbox.h
@@ -648,6 +648,7 @@ typedef struct isp_icb {
 #define	ICBXOPT_RIO_32BIT	2
 #define	ICBXOPT_RIO_16BIT_IOCB	3
 #define	ICBXOPT_RIO_32BIT_IOCB	4
+#define	ICBXOPT_ZIO		5
 
 #define	ICBZOPT_ENA_RDXFR_RDY	0x01
 #define	ICBZOPT_ENA_OOF		(1 << 6) /* out of order frame handling */