Index: head/sys/dev/hyperv/include/hyperv.h
===================================================================
--- head/sys/dev/hyperv/include/hyperv.h
+++ head/sys/dev/hyperv/include/hyperv.h
@@ -124,6 +124,8 @@
 	 unsigned char data[16];
 } __packed hv_guid;
 
+int snprintf_hv_guid(char *, size_t, const hv_guid *);
+
 #define HV_NIC_GUID							\
 	.data = {0x63, 0x51, 0x61, 0xF8, 0x3E, 0xDF, 0xc5, 0x46,	\
 		0x91, 0x3F, 0xF2, 0xD2, 0xF9, 0x65, 0xED, 0x0E}
Index: head/sys/dev/hyperv/utilities/hv_kvp.c
===================================================================
--- head/sys/dev/hyperv/utilities/hv_kvp.c
+++ head/sys/dev/hyperv/utilities/hv_kvp.c
@@ -304,28 +304,11 @@
 {
 	int err_ip, err_subnet, err_gway, err_dns, err_adap;
 	int UNUSED_FLAG = 1;
-	int guid_index;
 	struct hv_device *hv_dev;       /* GUID Data Structure */
 	hn_softc_t *sc;                 /* hn softc structure  */
 	char if_name[4];
-	unsigned char guid_instance[40];
-	char *guid_data = NULL;
 	char buf[39];
 
-	struct guid_extract {
-		char	a1[2];
-		char	a2[2];
-		char	a3[2];
-		char	a4[2];
-		char	b1[2];
-		char	b2[2];
-		char	c1[2];
-		char	c2[2];
-		char	d[4];
-		char	e[12];
-	};
-
-	struct guid_extract *id;
 	device_t *devs;
 	int devcnt;
 
@@ -352,17 +335,7 @@
 			/* Trying to find GUID of Network Device */
 			hv_dev = sc->hn_dev_obj;
 
-			for (guid_index = 0; guid_index < 16; guid_index++) {
-				sprintf(&guid_instance[guid_index * 2], "%02x",
-				    hv_dev->device_id.data[guid_index]);
-			}
-
-			guid_data = (char *)guid_instance;
-			id = (struct guid_extract *)guid_data;
-			snprintf(buf, sizeof(buf), "{%.2s%.2s%.2s%.2s-%.2s%.2s-%.2s%.2s-%.4s-%s}",
-			    id->a4, id->a3, id->a2, id->a1,
-			    id->b2, id->b1, id->c2, id->c1, id->d, id->e);
-			guid_data = NULL;
+			snprintf_hv_guid(buf, sizeof(buf), &hv_dev->device_id);
 			sprintf(if_name, "%s%d", "hn", device_get_unit(devs[devcnt]));
 
 			if (strncmp(buf, (char *)umsg->body.kvp_ip_val.adapter_id, 39) == 0) {
Index: head/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
===================================================================
--- head/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
+++ head/sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
@@ -59,6 +59,7 @@
 #include <sys/pcpu.h>
 #include <x86/apicvar.h>
 
+#include <dev/hyperv/include/hyperv.h>
 #include "hv_vmbus_priv.h"
 
 #include <contrib/dev/acpica/include/acpi.h>
@@ -300,15 +301,17 @@
 	return (child_dev);
 }
 
-static void
-print_dev_guid(struct hv_device *dev)
+int
+snprintf_hv_guid(char *buf, size_t sz, const hv_guid *guid)
 {
-	int i;
-	unsigned char guid_name[100];
-	for (i = 0; i < 32; i += 2)
-		sprintf(&guid_name[i], "%02x", dev->class_id.data[i / 2]);
-	if(bootverbose)
-		printf("VMBUS: Class ID: %s\n", guid_name);
+	int cnt;
+	const unsigned char *d = guid->data;
+
+	cnt = snprintf(buf, sz,
+		"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+		d[3], d[2], d[1], d[0], d[5], d[4], d[7], d[6],
+		d[8], d[9], d[10], d[11], d[12], d[13], d[14], d[15]);
+	return (cnt);
 }
 
 int
@@ -317,8 +320,11 @@
 	device_t child;
 	int ret = 0;
 
-	print_dev_guid(child_dev);
-
+	if (bootverbose) {
+		char name[40];
+		snprintf_hv_guid(name, sizeof(name), &child_dev->class_id);
+		printf("VMBUS: Class ID: %s\n", name);
+	}
 
 	child = device_add_child(vmbus_devp, NULL, -1);
 	child_dev->device = child;