diff --git a/src/northbridge/intel/sandybridge/registers/host_bridge.h b/src/northbridge/intel/sandybridge/registers/host_bridge.h
index 4814b94..9599871 100644
--- a/src/northbridge/intel/sandybridge/registers/host_bridge.h
+++ b/src/northbridge/intel/sandybridge/registers/host_bridge.h
@@ -52,6 +52,7 @@
 #define  CAPID_ECCDIS	(1 << 25)
 #define  CAPID_DDPCD	(1 << 14)
 #define  CAPID_PDCD	(1 << 12)
+#define  CAPID_WRTVREF	(1 <<  1)
 #define  CAPID_DDRSZ(x)	(((x) >> 19) & 0x3)
 
 #define CAPID0_B	0xe8	/* Capabilities Register B */