diff --git a/libfwupd/fwupd-common.c b/libfwupd/fwupd-common.c
index b274d9c77..61f96ba33 100644
--- a/libfwupd/fwupd-common.c
+++ b/libfwupd/fwupd-common.c
@@ -809,28 +809,39 @@ fwupd_guid_from_string(const gchar *guidstr,
 gchar *
 fwupd_guid_hash_data(const guint8 *data, gsize datasz, FwupdGuidFlags flags)
 {
-	const gchar *namespace_id = FWUPD_GUID_NAMESPACE_DEFAULT;
 	gsize digestlen = 20;
 	guint8 hash[20];
-	fwupd_guid_t uu_namespace;
 	fwupd_guid_t uu_new;
 	g_autoptr(GChecksum) csum = NULL;
+	const fwupd_guid_t uu_default = {0x6b,
+					 0xa7,
+					 0xb8,
+					 0x10,
+					 0x9d,
+					 0xad,
+					 0x11,
+					 0xd1,
+					 0x80,
+					 0xb4,
+					 0x00,
+					 0xc0,
+					 0x4f,
+					 0xd4,
+					 0x30,
+					 0xc8};
+	const fwupd_guid_t uu_microso = {0x70, 0xff, 0xd8, 0x12, 0x4c, 0x7f, 0x4c, 0x7d};
+	const fwupd_guid_t *uu_namespace = &uu_default;
 
-	g_return_val_if_fail(namespace_id != NULL, NULL);
 	g_return_val_if_fail(data != NULL, NULL);
 	g_return_val_if_fail(datasz != 0, NULL);
 
 	/* old MS GUID */
 	if (flags & FWUPD_GUID_FLAG_NAMESPACE_MICROSOFT)
-		namespace_id = FWUPD_GUID_NAMESPACE_MICROSOFT;
-
-	/* convert the namespace to binary: hardcoded BE, not @flags */
-	if (!fwupd_guid_from_string(namespace_id, &uu_namespace, FWUPD_GUID_FLAG_NONE, NULL))
-		return NULL;
+		uu_namespace = &uu_microso;
 
 	/* hash the namespace and then the string */
 	csum = g_checksum_new(G_CHECKSUM_SHA1);
-	g_checksum_update(csum, (guchar *)&uu_namespace, sizeof(uu_namespace));
+	g_checksum_update(csum, (guchar *)uu_namespace, sizeof(*uu_namespace));
 	g_checksum_update(csum, (guchar *)data, (gssize)datasz);
 	g_checksum_get_digest(csum, hash, &digestlen);
 
diff --git a/libfwupd/fwupd-self-test.c b/libfwupd/fwupd-self-test.c
index ba20c09c6..f087c0200 100644
--- a/libfwupd/fwupd-self-test.c
+++ b/libfwupd/fwupd-self-test.c
@@ -689,8 +689,10 @@ fwupd_common_device_id_func(void)
 static void
 fwupd_common_guid_func(void)
 {
+	const guint8 msbuf[] = "hello world!";
 	g_autofree gchar *guid1 = NULL;
 	g_autofree gchar *guid2 = NULL;
+	g_autofree gchar *guid3 = NULL;
 	g_autofree gchar *guid_be = NULL;
 	g_autofree gchar *guid_me = NULL;
 	fwupd_guid_t buf = {0x0};
@@ -716,6 +718,9 @@ fwupd_common_guid_func(void)
 	guid2 = fwupd_guid_hash_string("8086:0406");
 	g_assert_cmpstr(guid2, ==, "1fbd1f2c-80f4-5d7c-a6ad-35c7b9bd5486");
 
+	guid3 = fwupd_guid_hash_data(msbuf, sizeof(msbuf), FWUPD_GUID_FLAG_NAMESPACE_MICROSOFT);
+	g_assert_cmpstr(guid3, ==, "6836cfac-f77a-527f-b375-4f92f01449c5");
+
 	/* round-trip BE */
 	ret = fwupd_guid_from_string("00112233-4455-6677-8899-aabbccddeeff",
 				     &buf,