diff --git a/configure.ac b/configure.ac
index bcbf91975..a88b141a8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,6 +13,7 @@ AM_INIT_AUTOMAKE([1.9 no-dist-gzip dist-xz tar-ustar foreign])
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIR([m4])
 AC_PROG_LIBTOOL
+AC_PROG_CC_STDC
 
 m4_ifdef([GOBJECT_INTROSPECTION_CHECK], [GOBJECT_INTROSPECTION_CHECK([0.9.8])])
 AM_CONDITIONAL(HAVE_INTROSPECTION, test "x$found_introspection" = xyes)
diff --git a/src/fu-main.c b/src/fu-main.c
index b13e9f644..0576c4f78 100644
--- a/src/fu-main.c
+++ b/src/fu-main.c
@@ -205,7 +205,6 @@ static GVariant *
 fu_main_device_array_to_variant (GPtrArray *devices, GError **error)
 {
 	GVariantBuilder builder;
-	guint i;
 
 	/* no devices */
 	if (devices->len == 0) {
@@ -217,7 +216,7 @@ fu_main_device_array_to_variant (GPtrArray *devices, GError **error)
 	}
 
 	g_variant_builder_init (&builder, G_VARIANT_TYPE_ARRAY);
-	for (i = 0; i < devices->len; i++) {
+	for (guint i = 0; i < devices->len; i++) {
 		GVariant *tmp;
 		FuDeviceItem *item;
 		item = g_ptr_array_index (devices, i);
@@ -232,7 +231,6 @@ fu_main_load_plugins (GHashTable *plugins, GError **error)
 {
 	FuPlugin *plugin;
 	GModule *module;
-	GList *l;
 	const gchar *fn;
 	g_autofree gchar *plugin_dir = NULL;
 	g_autoptr(GDir) dir = NULL;
@@ -272,7 +270,7 @@ fu_main_load_plugins (GHashTable *plugins, GError **error)
 
 	/* start them all up */
 	values = g_hash_table_get_values (plugins);
-	for (l = values; l != NULL; l = l->next) {
+	for (GList *l = values; l != NULL; l = l->next) {
 		plugin = FU_PLUGIN (l->data);
 		if (!fu_plugin_run_startup (plugin, error))
 			return FALSE;
@@ -304,11 +302,8 @@ fu_main_item_free (FuDeviceItem *item)
 static FuDeviceItem *
 fu_main_get_item_by_id (FuMainPrivate *priv, const gchar *id)
 {
-	FuDeviceItem *item;
-	guint i;
-
-	for (i = 0; i < priv->devices->len; i++) {
-		item = g_ptr_array_index (priv->devices, i);
+	for (guint i = 0; i < priv->devices->len; i++) {
+		FuDeviceItem *item = g_ptr_array_index (priv->devices, i);
 		if (g_strcmp0 (fu_device_get_id (item->device), id) == 0)
 			return item;
 		if (g_strcmp0 (fu_device_get_equivalent_id (item->device), id) == 0)
@@ -320,11 +315,8 @@ fu_main_get_item_by_id (FuMainPrivate *priv, const gchar *id)
 static FuDeviceItem *
 fu_main_get_item_by_guid (FuMainPrivate *priv, const gchar *guid)
 {
-	FuDeviceItem *item;
-	guint i;
-
-	for (i = 0; i < priv->devices->len; i++) {
-		item = g_ptr_array_index (priv->devices, i);
+	for (guint i = 0; i < priv->devices->len; i++) {
+		FuDeviceItem *item = g_ptr_array_index (priv->devices, i);
 		if (fu_device_has_guid (item->device, guid))
 			return item;
 	}
@@ -334,11 +326,8 @@ fu_main_get_item_by_guid (FuMainPrivate *priv, const gchar *guid)
 static FuProvider *
 fu_main_get_provider_by_name (FuMainPrivate *priv, const gchar *name)
 {
-	FuProvider *provider;
-	guint i;
-
-	for (i = 0; i < priv->providers->len; i++) {
-		provider = g_ptr_array_index (priv->providers, i);
+	for (guint i = 0; i < priv->providers->len; i++) {
+		FuProvider *provider = g_ptr_array_index (priv->providers, i);
 		if (g_strcmp0 (fu_provider_get_name (provider), name) == 0)
 			return provider;
 	}
@@ -469,10 +458,8 @@ fu_main_on_battery (FuMainPrivate *priv)
 static gboolean
 fu_main_provider_unlock_authenticated (FuMainAuthHelper *helper, GError **error)
 {
-	guint i;
-
 	/* check the devices still exists */
-	for (i = 0; i < helper->devices->len; i ++) {
+	for (guint i = 0; i < helper->devices->len; i ++) {
 		FuDeviceItem *item;
 		FuDevice *device = g_ptr_array_index (helper->devices, i);
 
@@ -508,10 +495,9 @@ fu_main_provider_update_authenticated (FuMainAuthHelper *helper, GError **error)
 {
 	FuDeviceItem *item;
 	FuPlugin *plugin;
-	guint i;
 
 	/* check the devices still exists */
-	for (i = 0; i < helper->devices->len; i ++) {
+	for (guint i = 0; i < helper->devices->len; i ++) {
 		FuDevice *device = g_ptr_array_index (helper->devices, i);
 		item = fu_main_get_item_by_id (helper->priv,
 					       fu_device_get_id (device));
@@ -549,7 +535,7 @@ fu_main_provider_update_authenticated (FuMainAuthHelper *helper, GError **error)
 	}
 
 	/* run the correct providers for each device */
-	for (i = 0; i < helper->devices->len; i ++) {
+	for (guint i = 0; i < helper->devices->len; i ++) {
 		FuDevice *device = g_ptr_array_index (helper->devices, i);
 		GBytes *blob_fw = g_ptr_array_index (helper->blob_fws, i);
 		item = fu_main_get_item_by_id (helper->priv,
@@ -630,20 +616,17 @@ fu_main_check_authorization_cb (GObject *source, GAsyncResult *res, gpointer use
 static gchar *
 fu_main_get_guids_from_store (AsStore *store)
 {
-	AsApp *app;
 	AsProvide *prov;
 	GPtrArray *provides;
 	GPtrArray *apps;
 	GString *str = g_string_new ("");
-	guint i;
-	guint j;
 
 	/* return a string with all the firmware apps in the store */
 	apps = as_store_get_apps (store);
-	for (i = 0; i < apps->len; i++) {
-		app = AS_APP (g_ptr_array_index (apps, i));
+	for (guint i = 0; i < apps->len; i++) {
+		AsApp *app = AS_APP (g_ptr_array_index (apps, i));
 		provides = as_app_get_provides (app);
-		for (j = 0; j < provides->len; j++) {
+		for (guint j = 0; j < provides->len; j++) {
 			prov = AS_PROVIDE (g_ptr_array_index (provides, j));
 			if (as_provide_get_kind (prov) != AS_PROVIDE_KIND_FIRMWARE_FLASHED)
 				continue;
@@ -661,19 +644,19 @@ fu_main_vendor_quirk_release_version (AsApp *app)
 {
 	AsVersionParseFlag flags = AS_VERSION_PARSE_FLAG_USE_TRIPLET;
 	GPtrArray *releases;
-	guint i;
 
 	/* no quirk required */
 	if (as_app_get_kind (app) != AS_APP_KIND_FIRMWARE)
 		return;
 
-        for (i = 0; quirk_table[i].identifier != NULL; i++)
+	for (guint i = 0; quirk_table[i].identifier != NULL; i++) {
 		if (g_str_has_prefix (as_app_get_id(app), quirk_table[i].identifier))
 			flags = quirk_table[i].flags;
+	}
 
 	/* fix each release */
 	releases = as_app_get_releases (app);
-	for (i = 0; i < releases->len; i++) {
+	for (guint i = 0; i < releases->len; i++) {
 		AsRelease *rel;
 		const gchar *version;
 		guint64 ver_uint32;
@@ -704,11 +687,8 @@ fu_main_vendor_quirk_release_version (AsApp *app)
 static AsApp *
 fu_main_store_get_app_by_guids (AsStore *store, FuDevice *device)
 {
-	GPtrArray *guids;
-	guint i;
-
-	guids = fu_device_get_guids (device);
-	for (i = 0; i < guids->len; i++) {
+	GPtrArray *guids = fu_device_get_guids (device);
+	for (guint i = 0; i < guids->len; i++) {
 		AsApp *app = NULL;
 		app = as_store_get_app_by_provide (store,
 						   AS_PROVIDE_KIND_FIRMWARE_FLASHED,
@@ -849,7 +829,6 @@ fu_main_update_helper_for_device (FuMainAuthHelper *helper,
 static gboolean
 fu_main_update_helper (FuMainAuthHelper *helper, GError **error)
 {
-	guint i;
 	g_autoptr(GError) error_first = NULL;
 
 	/* load store file which also decompresses firmware */
@@ -859,7 +838,7 @@ fu_main_update_helper (FuMainAuthHelper *helper, GError **error)
 
 	/* we've specified a specific device; failure is critical */
 	if (helper->devices->len > 0) {
-		for (i = 0; i < helper->devices->len; i ++) {
+		for (guint i = 0; i < helper->devices->len; i ++) {
 			FuDevice *device = g_ptr_array_index (helper->devices, i);
 			if (!fu_main_update_helper_for_device (helper, device, error))
 				return FALSE;
@@ -869,7 +848,7 @@ fu_main_update_helper (FuMainAuthHelper *helper, GError **error)
 
 	/* if we've not chosen a device, try and find anything in the
 	 * cabinet 'store' that matches any installed device and is updatable */
-	for (i = 0; i < helper->priv->devices->len; i++) {
+	for (guint i = 0; i < helper->priv->devices->len; i++) {
 		AsApp *app;
 		FuDeviceItem *item;
 		g_autoptr(GError) error_local = NULL;
@@ -963,7 +942,6 @@ fu_main_get_item_by_id_fallback_pending (FuMainPrivate *priv, const gchar *id, G
 	FuDeviceItem *item = NULL;
 	FwupdUpdateState update_state;
 	const gchar *tmp;
-	guint i;
 	g_autoptr(GPtrArray) devices = NULL;
 
 	/* not a wildcard */
@@ -982,7 +960,7 @@ fu_main_get_item_by_id_fallback_pending (FuMainPrivate *priv, const gchar *id, G
 	devices = fu_pending_get_devices (priv->pending, error);
 	if (devices == NULL)
 		return NULL;
-	for (i = 0; i < devices->len; i++) {
+	for (guint i = 0; i < devices->len; i++) {
 		dev = g_ptr_array_index (devices, i);
 		update_state = fu_device_get_update_state (dev);
 		if (update_state == FWUPD_UPDATE_STATE_UNKNOWN)
@@ -1027,13 +1005,12 @@ fu_main_get_action_id_for_device (FuMainAuthHelper *helper)
 {
 	gboolean all_removable = TRUE;
 	gboolean is_trusted;
-	guint i;
 
 	/* only test the payload */
 	is_trusted = (helper->trust_flags & FWUPD_TRUST_FLAG_PAYLOAD) > 0;
 
 	/* any non-removable means false */
-	for (i = 0; i < helper->devices->len; i ++) {
+	for (guint i = 0; i < helper->devices->len; i ++) {
 		FuDevice *device = g_ptr_array_index (helper->devices, i);
 		if (fu_device_has_flag (device, FU_DEVICE_FLAG_INTERNAL)) {
 			all_removable = FALSE;
@@ -1062,7 +1039,6 @@ static gboolean
 fu_main_daemon_update_metadata (FuMainPrivate *priv, gint fd, gint fd_sig, GError **error)
 {
 	const guint8 *data;
-	guint i;
 	gsize size;
 	GPtrArray *apps;
 	g_autofree gchar *xml = NULL;
@@ -1137,7 +1113,7 @@ fu_main_daemon_update_metadata (FuMainPrivate *priv, gint fd, gint fd_sig, GErro
 	/* add the new application from the store */
 	as_store_remove_all (priv->store);
 	apps = as_store_get_apps (store);
-	for (i = 0; i < apps->len; i++) {
+	for (guint i = 0; i < apps->len; i++) {
 		AsApp *app = g_ptr_array_index (apps, i);
 		as_store_add_app (priv->store, app);
 	}
@@ -1159,11 +1135,8 @@ fu_main_daemon_update_metadata (FuMainPrivate *priv, gint fd, gint fd_sig, GErro
 static gboolean
 fu_main_store_delay_cb (gpointer user_data)
 {
-	AsApp *app;
-	GPtrArray *apps;
-	guint i;
-	FuDeviceItem *item;
 	FuMainPrivate *priv = (FuMainPrivate *) user_data;
+	GPtrArray *apps;
 
 	/* print what we've got */
 	apps = as_store_get_apps (priv->store);
@@ -1171,8 +1144,8 @@ fu_main_store_delay_cb (gpointer user_data)
 		g_debug ("no devices in store");
 	} else {
 		g_debug ("devices now in store:");
-		for (i = 0; i < apps->len; i++) {
-			app = g_ptr_array_index (apps, i);
+		for (guint i = 0; i < apps->len; i++) {
+			AsApp *app = g_ptr_array_index (apps, i);
 			g_debug ("%i\t%s\t%s", i + 1,
 				 as_app_get_id (app),
 				 as_app_get_name (app, NULL));
@@ -1180,8 +1153,8 @@ fu_main_store_delay_cb (gpointer user_data)
 	}
 
 	/* are any devices now supported? */
-	for (i = 0; i < priv->devices->len; i++) {
-		item = g_ptr_array_index (priv->devices, i);
+	for (guint i = 0; i < priv->devices->len; i++) {
+		FuDeviceItem *item = g_ptr_array_index (priv->devices, i);
 		if (fu_main_get_updates_item_update (priv, item))
 			fu_main_emit_device_changed (priv, item->device);
 	}
@@ -1207,7 +1180,6 @@ fu_main_get_updates_item_update (FuMainPrivate *priv, FuDeviceItem *item)
 	GPtrArray *releases;
 	const gchar *tmp;
 	const gchar *version;
-	guint i;
 	g_autoptr(GPtrArray) updates_list = NULL;
 
 	/* get device version */
@@ -1295,7 +1267,7 @@ fu_main_get_updates_item_update (FuMainPrivate *priv, FuDeviceItem *item)
 	/* get the list of releases newer than the one installed */
 	updates_list = g_ptr_array_new ();
 	releases = as_app_get_releases (app);
-	for (i = 0; i < releases->len; i++) {
+	for (guint i = 0; i < releases->len; i++) {
 		rel = g_ptr_array_index (releases, i);
 		if (as_utils_vercmp (as_release_get_version (rel), version) < 0)
 			continue;
@@ -1315,7 +1287,7 @@ fu_main_get_updates_item_update (FuMainPrivate *priv, FuDeviceItem *item)
 		update_desc = g_string_new ("");
 
 		/* get the descriptions with a version prefix */
-		for (i = 0; i < updates_list->len; i++) {
+		for (guint i = 0; i < updates_list->len; i++) {
 			rel = g_ptr_array_index (updates_list, i);
 			g_string_append_printf (update_desc,
 						"<p>%s:</p>%s",
@@ -1330,17 +1302,13 @@ fu_main_get_updates_item_update (FuMainPrivate *priv, FuDeviceItem *item)
 	return TRUE;
 }
 
+/* find any updates using the AppStream metadata */
 static GPtrArray *
 fu_main_get_updates (FuMainPrivate *priv, GError **error)
 {
-	GPtrArray *updates;
-	FuDeviceItem *item;
-	guint i;
-
-	/* find any updates using the AppStream metadata */
-	updates = g_ptr_array_new ();
-	for (i = 0; i < priv->devices->len; i++) {
-		item = g_ptr_array_index (priv->devices, i);
+	GPtrArray *updates = g_ptr_array_new ();
+	for (guint i = 0; i < priv->devices->len; i++) {
+		FuDeviceItem *item = g_ptr_array_index (priv->devices, i);
 		if (fu_main_get_updates_item_update (priv, item))
 			g_ptr_array_add (updates, item);
 	}
@@ -1388,12 +1356,11 @@ fu_main_get_result_from_app (FuMainPrivate *priv, AsApp *app, GError **error)
 	AsChecksum * csum_tmp;
 	const gchar *fn;
 	GPtrArray *provides;
-	guint i;
 	g_autoptr(FwupdResult) res = NULL;
 
 	res = fwupd_result_new ();
 	provides = as_app_get_provides (app);
-	for (i = 0; i < provides->len; i++) {
+	for (guint i = 0; i < provides->len; i++) {
 		AsProvide *prov = AS_PROVIDE (g_ptr_array_index (provides, i));
 		FuDeviceItem *item;
 		const gchar *guid;
@@ -1456,7 +1423,6 @@ fu_main_get_details_from_fd (FuMainPrivate *priv, gint fd, GError **error)
 {
 	AsApp *app = NULL;
 	GPtrArray *apps;
-	guint i;
 	g_autoptr(AsStore) store = NULL;
 	g_autoptr(FwupdResult) res = NULL;
 
@@ -1476,7 +1442,7 @@ fu_main_get_details_from_fd (FuMainPrivate *priv, gint fd, GError **error)
 	if (apps->len > 1) {
 		/* we've got a .cab file with multiple components,
 		 * so try to find the first thing that's installed */
-		for (i = 0; i < priv->devices->len; i++) {
+		for (guint i = 0; i < priv->devices->len; i++) {
 			FuDeviceItem *item = g_ptr_array_index (priv->devices, i);
 			app = fu_main_store_get_app_by_guids (store, item->device);
 			if (app != NULL)
@@ -1500,7 +1466,6 @@ fu_main_get_details_local_from_fd (FuMainPrivate *priv, gint fd, GError **error)
 {
 	GPtrArray *apps;
 	GVariantBuilder builder;
-	guint i;
 	g_autoptr(AsStore) store = NULL;
 
 	store = fu_main_get_store_from_fd (priv, fd, error);
@@ -1519,7 +1484,7 @@ fu_main_get_details_local_from_fd (FuMainPrivate *priv, gint fd, GError **error)
 
 	/* create results with all the metadata in */
 	g_variant_builder_init (&builder, G_VARIANT_TYPE_ARRAY);
-	for (i = 0; i < apps->len; i++) {
+	for (guint i = 0; i < apps->len; i++) {
 		g_autoptr(FwupdResult) res = NULL;
 		AsApp *app = g_ptr_array_index (apps, i);
 		GVariant *tmp;
@@ -2049,15 +2014,13 @@ fu_main_daemon_get_property (GDBusConnection *connection_, const gchar *sender,
 static void
 fu_main_providers_coldplug (FuMainPrivate *priv)
 {
-	FuProvider *provider;
-	guint i;
 	g_autoptr(AsProfileTask) ptask = NULL;
 
 	ptask = as_profile_start_literal (priv->profile, "FuMain:coldplug");
-	for (i = 0; i < priv->providers->len; i++) {
+	for (guint i = 0; i < priv->providers->len; i++) {
 		g_autoptr(GError) error = NULL;
 		g_autoptr(AsProfileTask) ptask2 = NULL;
-		provider = g_ptr_array_index (priv->providers, i);
+		FuProvider *provider = g_ptr_array_index (priv->providers, i);
 		ptask2 = as_profile_start (priv->profile,
 					   "FuMain:coldplug{%s}",
 					   fu_provider_get_name (provider));
diff --git a/src/fu-pending.c b/src/fu-pending.c
index e6b0115c4..6391681f2 100644
--- a/src/fu-pending.c
+++ b/src/fu-pending.c
@@ -230,14 +230,13 @@ fu_pending_device_sqlite_cb (void *data,
 {
 	GPtrArray *array = (GPtrArray *) data;
 	FwupdResult *res;
-	gint i;
 
 	/* create new result */
 	res = fwupd_result_new ();
 	g_ptr_array_add (array, res);
 
 	g_debug ("FuPending: got sql result %s", argv[0]);
-	for (i = 0; i < argc; i++) {
+	for (gint i = 0; i < argc; i++) {
 		if (g_strcmp0 (col_name[i], "device_id") == 0) {
 			fwupd_result_set_device_id (res, argv[i]);
 			continue;
diff --git a/src/fu-provider-dell.c b/src/fu-provider-dell.c
index a5182768a..4ef45a6ca 100644
--- a/src/fu-provider-dell.c
+++ b/src/fu-provider-dell.c
@@ -186,7 +186,6 @@ fu_provider_dell_match_dock_component(const gchar *query_str,
 				 const efi_guid_t **guid_out,
 				 const gchar **name_out)
 {
-	guint i;
 	const DOCK_DESCRIPTION list[] = {
 		{WD15_EC_GUID, WD15_EC_STR, EC_DESC},
 		{TB15_EC_GUID, TB15_EC_STR, EC_DESC},
@@ -198,7 +197,7 @@ fu_provider_dell_match_dock_component(const gchar *query_str,
 		{LEGACY_CBL_GUID, LEGACY_CBL_STR, LEGACY_CBL_DESC},
 	};
 
-	for (i = 0; i < G_N_ELEMENTS(list); i++) {
+	for (guint i = 0; i < G_N_ELEMENTS(list); i++) {
 		if (g_strcmp0 (query_str,
 			       list[i].query) == 0) {
 			*guid_out = &list[i].guid;
@@ -215,11 +214,10 @@ fu_provider_dell_inject_fake_data (FuProviderDell *provider_dell,
 				   guint8 *buf)
 {
 	FuProviderDellPrivate *priv = GET_PRIVATE (provider_dell);
-	guint i;
 
 	if (!priv->fake_smbios)
 		return;
-	for (i = 0; i < 4; i++)
+	for (guint i = 0; i < 4; i++)
 		priv->fake_output[i] = output[i];
 	priv->fake_vid = vid;
 	priv->fake_pid = pid;
@@ -249,10 +247,9 @@ fu_provider_dell_execute_simple_smi (FuProviderDell *provider_dell,
 				     guint32  *args, guint32 *out)
 {
 	FuProviderDellPrivate *priv = GET_PRIVATE (provider_dell);
-	guint i;
 
 	if (priv->fake_smbios) {
-		for (i = 0; i < 4; i++)
+		for (guint i = 0; i < 4; i++)
 			out[i] = priv->fake_output[i];
 		return TRUE;
 	}
@@ -317,7 +314,6 @@ fu_provider_dell_device_free (FuProviderDellDockItem *item)
 static AsVersionParseFlag
 fu_provider_dell_get_version_format (void)
 {
-	guint i;
 	g_autofree gchar *content = NULL;
 
 	/* any vendors match */
@@ -325,7 +321,7 @@ fu_provider_dell_get_version_format (void)
 				  &content, NULL, NULL))
 		return AS_VERSION_PARSE_FLAG_USE_TRIPLET;
 	g_strchomp (content);
-	for (i = 0; quirk_table[i].sys_vendor != NULL; i++) {
+	for (guint i = 0; quirk_table[i].sys_vendor != NULL; i++) {
 		if (g_strcmp0 (content, quirk_table[i].sys_vendor) == 0)
 			return quirk_table[i].flags;
 	}
@@ -425,7 +421,6 @@ fu_provider_dell_device_added_cb (GUsbContext *ctx,
 	guint buf_size;
 	g_autoptr(fu_dell_smi_obj) smi = NULL;
 	gint result;
-	gint i;
 	guint32 location;
 	const efi_guid_t *guid_raw = NULL;
 	efi_guid_t tmpguid;
@@ -501,7 +496,7 @@ fu_provider_dell_device_added_cb (GUsbContext *ctx,
 	g_debug ("Dell: dock component count: %d", dock_info->component_count);
 	parse_flags = fu_provider_dell_get_version_format ();
 
-	for (i = 0; i < dock_info->component_count; i++) {
+	for (guint i = 0; i < dock_info->component_count; i++) {
 		if (i > MAX_COMPONENTS) {
 			g_debug ("Dell: Too many components.  Invalid: #%d", i);
 			break;
@@ -640,7 +635,7 @@ fu_provider_dell_device_removed_cb (GUsbContext *ctx,
 		return;
 
 	/* remove any components already in database? */
-	for (i = 0; i < G_N_ELEMENTS(guids); i++) {
+	for (guint i = 0; i < G_N_ELEMENTS(guids); i++) {
 		guid_raw = &guids[i];
 		guid_str = g_strdup ("00000000-0000-0000-0000-000000000000");
 		efi_guid_to_str (guid_raw, &guid_str);
@@ -731,7 +726,6 @@ fu_provider_dell_detect_tpm (FuProvider *provider, GError **error)
 	const gchar *tpm_mode;
 	const gchar *tpm_mode_alt;
 	guint16 system_id = 0;
-	guint i;
 	gboolean can_switch_modes = TRUE;
 	g_autofree gchar *pretty_tpm_name_alt = NULL;
 	g_autofree gchar *pretty_tpm_name = NULL;
@@ -792,7 +786,7 @@ fu_provider_dell_detect_tpm (FuProvider *provider, GError **error)
 	if (!priv->fake_smbios)
 		system_id = sysinfo_get_dell_system_id ();
 
-	for (i = 0; i < G_N_ELEMENTS(tpm_switch_blacklist); i++) {
+	for (guint i = 0; i < G_N_ELEMENTS(tpm_switch_blacklist); i++) {
 		if (tpm_switch_blacklist[i] == system_id) {
 			can_switch_modes = FALSE;
 		}
diff --git a/src/fu-provider-rpi.c b/src/fu-provider-rpi.c
index db7b720f9..ee0adf346 100644
--- a/src/fu-provider-rpi.c
+++ b/src/fu-provider-rpi.c
@@ -55,7 +55,6 @@ fu_provider_rpi_strstr (const guint8 *haystack,
 			const gchar *needle,
 			guint *offset)
 {
-	guint i;
 	guint needle_len;
 
 	if (needle == NULL || needle[0] == '\0')
@@ -65,7 +64,7 @@ fu_provider_rpi_strstr (const guint8 *haystack,
 	needle_len = strlen (needle);
 	if (needle_len > haystack_len)
 		return NULL;
-	for (i = 0; i < haystack_len - needle_len; i++) {
+	for (guint i = 0; i < haystack_len - needle_len; i++) {
 		if (memcmp (haystack + i, needle, needle_len) == 0) {
 			if (offset != NULL)
 				*offset = i + needle_len;
diff --git a/src/fu-provider-udev.c b/src/fu-provider-udev.c
index 9c5ffbc4b..e6da1fee5 100644
--- a/src/fu-provider-udev.c
+++ b/src/fu-provider-udev.c
@@ -240,19 +240,17 @@ fu_provider_udev_coldplug (FuProvider *provider, GError **error)
 	FuProviderUdev *provider_udev = FU_PROVIDER_UDEV (provider);
 	FuProviderUdevPrivate *priv = GET_PRIVATE (provider_udev);
 	GList *devices;
-	GList *l;
 	GUdevDevice *udev_device;
 	const gchar *devclass[] = { "usb", "pci", NULL };
-	guint i;
 	g_autoptr(AsProfile) profile = as_profile_new ();
 
 	/* get all devices of class */
-	for (i = 0; devclass[i] != NULL; i++) {
+	for (guint i = 0; devclass[i] != NULL; i++) {
 		g_autoptr(AsProfileTask) ptask = NULL;
 		ptask = as_profile_start (profile, "FuProviderUdev:coldplug{%s}", devclass[i]);
 		devices = g_udev_client_query_by_subsystem (priv->gudev_client,
 							    devclass[i]);
-		for (l = devices; l != NULL; l = l->next) {
+		for (GList *l = devices; l != NULL; l = l->next) {
 			udev_device = l->data;
 			fu_provider_udev_client_add (provider_udev, udev_device);
 		}
diff --git a/src/fu-provider-uefi.c b/src/fu-provider-uefi.c
index 08b0a7c42..f4c860605 100644
--- a/src/fu-provider-uefi.c
+++ b/src/fu-provider-uefi.c
@@ -222,14 +222,13 @@ fu_provider_uefi_update (FuProvider *provider,
 static AsVersionParseFlag
 fu_provider_uefi_get_version_format (void)
 {
-	guint i;
 	g_autofree gchar *content = NULL;
 	/* any vendors match */
 	if (!g_file_get_contents ("/sys/class/dmi/id/sys_vendor",
 				  &content, NULL, NULL))
 		return AS_VERSION_PARSE_FLAG_USE_TRIPLET;
 	g_strchomp (content);
-	for (i = 0; quirk_table[i].sys_vendor != NULL; i++) {
+	for (guint i = 0; quirk_table[i].sys_vendor != NULL; i++) {
 		if (g_strcmp0 (content, quirk_table[i].sys_vendor) == 0)
 			return quirk_table[i].flags;
 	}
diff --git a/src/fu-provider.c b/src/fu-provider.c
index 9981c8a73..73af336f1 100644
--- a/src/fu-provider.c
+++ b/src/fu-provider.c
@@ -107,7 +107,6 @@ fu_provider_schedule_update (FuProvider *provider,
 			     GError **error)
 {
 	gchar tmpname[] = {"XXXXXX.cap"};
-	guint i;
 	g_autofree gchar *dirname = NULL;
 	g_autofree gchar *filename = NULL;
 	g_autoptr(FwupdResult) res_tmp = NULL;
@@ -135,7 +134,7 @@ fu_provider_schedule_update (FuProvider *provider,
 	}
 
 	/* get a random filename */
-	for (i = 0; i < 6; i++)
+	for (guint i = 0; i < 6; i++)
 		tmpname[i] = g_random_int_range ('A', 'Z');
 	filename = g_build_filename (dirname, tmpname, NULL);
 
diff --git a/src/fu-rom.c b/src/fu-rom.c
index e5ade0ad3..aab7753af 100644
--- a/src/fu-rom.c
+++ b/src/fu-rom.c
@@ -96,7 +96,6 @@ fu_rom_kind_to_string (FuRomKind kind)
 static guint8 *
 fu_rom_pci_strstr (FuRomPciHeader *hdr, const gchar *needle)
 {
-	guint i;
 	guint needle_len;
 	guint8 *haystack;
 	gsize haystack_len;
@@ -112,7 +111,7 @@ fu_rom_pci_strstr (FuRomPciHeader *hdr, const gchar *needle)
 	needle_len = strlen (needle);
 	if (needle_len > haystack_len)
 		return NULL;
-	for (i = 0; i < haystack_len - needle_len; i++) {
+	for (guint i = 0; i < haystack_len - needle_len; i++) {
 		if (memcmp (haystack + i, needle, needle_len) == 0)
 			return &haystack[i];
 	}
@@ -138,14 +137,13 @@ static gchar *
 fu_rom_get_hex_dump (guint8 *buffer, gssize sz)
 {
 	GString *str = NULL;
-	guint i;
 	str = g_string_new ("");
 	if (sz <= 0)
 		return NULL;
-	for (i = 0; i < (guint) sz; i++)
+	for (guint i = 0; i < (guint) sz; i++)
 		g_string_append_printf (str, "%02x ", buffer[i]);
 	g_string_append (str, "   ");
-	for (i = 0; i < (guint) sz; i++) {
+	for (guint i = 0; i < (guint) sz; i++) {
 		gchar tmp = '?';
 		if (g_ascii_isprint (buffer[i]))
 			tmp = buffer[i];
@@ -229,8 +227,7 @@ static guint8
 fu_rom_pci_header_get_checksum (FuRomPciHeader *hdr)
 {
 	guint8 chksum_check = 0x00;
-	guint i;
-	for (i = 0; i < hdr->rom_len; i++)
+	for (guint i = 0; i < hdr->rom_len; i++)
 		chksum_check += hdr->rom_data[i];
 	return chksum_check;
 }
@@ -304,9 +301,8 @@ fu_rom_extract_all (FuRom *rom, const gchar *path, GError **error)
 {
 	FuRomPrivate *priv = GET_PRIVATE (rom);
 	FuRomPciHeader *hdr;
-	guint i;
 
-	for (i = 0; i < priv->hdrs->len; i++) {
+	for (guint i = 0; i < priv->hdrs->len; i++) {
 		g_autofree gchar *fn = NULL;
 		hdr = g_ptr_array_index (priv->hdrs, i);
 		fn = g_strdup_printf ("%s/%02i.bin", path, i);
@@ -327,7 +323,6 @@ fu_rom_find_and_blank_serial_numbers (FuRom *rom)
 {
 	FuRomPrivate *priv = GET_PRIVATE (rom);
 	FuRomPciHeader *hdr;
-	guint i;
 	guint8 *tmp;
 
 	/* bail if not likely */
@@ -337,7 +332,7 @@ fu_rom_find_and_blank_serial_numbers (FuRom *rom)
 		return;
 	}
 
-	for (i = 0; i < priv->hdrs->len; i++) {
+	for (guint i = 0; i < priv->hdrs->len; i++) {
 		hdr = g_ptr_array_index (priv->hdrs, i);
 		g_debug ("looking for PPID at 0x%04x", hdr->rom_offset);
 		tmp = fu_rom_pci_strstr (hdr, "PPID");
@@ -508,10 +503,9 @@ fu_rom_find_version_intel (FuRomPciHeader *hdr)
 	/* 2175_RYan PC 14.34  06/06/2013  21:27:53 */
 	str = (gchar *) fu_rom_pci_strstr (hdr, "Build Number:");
 	if (str != NULL) {
-		guint i;
 		g_auto(GStrv) split = NULL;
 		split = g_strsplit (str + 14, " ", -1);
-		for (i = 0; split[i] != NULL; i++) {
+		for (guint i = 0; split[i] != NULL; i++) {
 			if (g_strstr_len (split[i], -1, ".") == NULL)
 				continue;
 			return g_strdup (split[i]);
@@ -565,7 +559,6 @@ fu_rom_load_file (FuRom *rom, GFile *file, FuRomLoadFlags flags,
 	gssize sz;
 	guint32 jump = 0;
 	guint hdr_sz = 0;
-	guint i;
 	guint number_reads = 0;
 	g_autoptr(GError) error_local = NULL;
 	g_autofree gchar *fn = NULL;
@@ -655,7 +648,7 @@ fu_rom_load_file (FuRom *rom, GFile *file, FuRomLoadFlags flags,
 			gboolean found_data = FALSE;
 
 			/* check it's not just NUL padding */
-			for (i = 0; i < hdr_sz + jump; i++) {
+			for (guint i = 0; i < hdr_sz + jump; i++) {
 				if (buffer[hdr_sz + jump + i] != 0x00) {
 					found_data = TRUE;
 					break;
@@ -706,7 +699,7 @@ fu_rom_load_file (FuRom *rom, GFile *file, FuRomLoadFlags flags,
 	}
 
 	/* print all headers */
-	for (i = 0; i < priv->hdrs->len; i++) {
+	for (guint i = 0; i < priv->hdrs->len; i++) {
 		hdr = g_ptr_array_index (priv->hdrs, i);
 		fu_rom_pci_print_header (hdr);
 	}
@@ -755,7 +748,7 @@ fu_rom_load_file (FuRom *rom, GFile *file, FuRomLoadFlags flags,
 	/* update checksum */
 	if (flags & FU_ROM_LOAD_FLAG_BLANK_PPID)
 		fu_rom_find_and_blank_serial_numbers (rom);
-	for (i = 0; i < priv->hdrs->len; i++) {
+	for (guint i = 0; i < priv->hdrs->len; i++) {
 		hdr = g_ptr_array_index (priv->hdrs, i);
 		g_checksum_update (priv->checksum_wip, hdr->rom_data, hdr->rom_len);
 	}
diff --git a/src/fu-self-test.c b/src/fu-self-test.c
index 3e8557ab2..9b7d0fcd5 100644
--- a/src/fu-self-test.c
+++ b/src/fu-self-test.c
@@ -53,7 +53,6 @@ fu_test_get_filename (const gchar *filename)
 static void
 fu_rom_func (void)
 {
-	guint i;
 	struct {
 		FuRomKind kind;
 		const gchar *fn;
@@ -95,7 +94,7 @@ fu_rom_func (void)
 		    { FU_ROM_KIND_UNKNOWN, NULL, NULL, NULL, 0x0000, 0x0000 }
 		};
 
-	for (i = 0; data[i].fn != NULL; i++) {
+	for (guint i = 0; data[i].fn != NULL; i++) {
 		gboolean ret;
 		g_autoptr(GError) error = NULL;
 		g_autofree gchar *filename = NULL;
diff --git a/src/fu-util.c b/src/fu-util.c
index 5a338b2c5..b39a4c42d 100644
--- a/src/fu-util.c
+++ b/src/fu-util.c
@@ -92,8 +92,6 @@ fu_util_add (GPtrArray *array,
 	     const gchar *description,
 	     FuUtilPrivateCb callback)
 {
-	guint i;
-	FuUtilItem *item;
 	g_auto(GStrv) names = NULL;
 
 	g_return_if_fail (name != NULL);
@@ -102,8 +100,8 @@ fu_util_add (GPtrArray *array,
 
 	/* add each one */
 	names = g_strsplit (name, ",", -1);
-	for (i = 0; names[i] != NULL; i++) {
-		item = g_new0 (FuUtilItem, 1);
+	for (guint i = 0; names[i] != NULL; i++) {
+		FuUtilItem *item = g_new0 (FuUtilItem, 1);
 		item->name = g_strdup (names[i]);
 		if (i == 0) {
 			item->description = g_strdup (description);
@@ -121,17 +119,14 @@ fu_util_add (GPtrArray *array,
 static gchar *
 fu_util_get_descriptions (GPtrArray *array)
 {
-	guint i;
-	guint j;
 	guint len;
 	const guint max_len = 35;
-	FuUtilItem *item;
 	GString *string;
 
 	/* print each command */
 	string = g_string_new ("");
-	for (i = 0; i < array->len; i++) {
-		item = g_ptr_array_index (array, i);
+	for (guint i = 0; i < array->len; i++) {
+		FuUtilItem *item = g_ptr_array_index (array, i);
 		g_string_append (string, "  ");
 		g_string_append (string, item->name);
 		len = strlen (item->name) + 2;
@@ -141,13 +136,13 @@ fu_util_get_descriptions (GPtrArray *array)
 			len += strlen (item->arguments) + 1;
 		}
 		if (len < max_len) {
-			for (j = len; j < max_len + 1; j++)
+			for (guint j = len; j < max_len + 1; j++)
 				g_string_append_c (string, ' ');
 			g_string_append (string, item->description);
 			g_string_append_c (string, '\n');
 		} else {
 			g_string_append_c (string, '\n');
-			for (j = 0; j < max_len + 1; j++)
+			for (guint j = 0; j < max_len + 1; j++)
 				g_string_append_c (string, ' ');
 			g_string_append (string, item->description);
 			g_string_append_c (string, '\n');
@@ -164,12 +159,9 @@ fu_util_get_descriptions (GPtrArray *array)
 static gboolean
 fu_util_run (FuUtilPrivate *priv, const gchar *command, gchar **values, GError **error)
 {
-	guint i;
-	FuUtilItem *item;
-
 	/* find command */
-	for (i = 0; i < priv->cmd_array->len; i++) {
-		item = g_ptr_array_index (priv->cmd_array, i);
+	for (guint i = 0; i < priv->cmd_array->len; i++) {
+		FuUtilItem *item = g_ptr_array_index (priv->cmd_array, i);
 		if (g_strcmp0 (item->name, command) == 0)
 			return item->callback (priv, values, error);
 	}
@@ -225,8 +217,6 @@ fu_util_status_changed_cb (FwupdClient *client,
 static gboolean
 fu_util_get_devices (FuUtilPrivate *priv, gchar **values, GError **error)
 {
-	FwupdResult *res;
-	guint i;
 	g_autoptr(GPtrArray) results = NULL;
 
 	/* get results from daemon */
@@ -241,9 +231,9 @@ fu_util_get_devices (FuUtilPrivate *priv, gchar **values, GError **error)
 		return TRUE;
 	}
 
-	for (i = 0; i < results->len; i++) {
+	for (guint i = 0; i < results->len; i++) {
 		g_autofree gchar *tmp = NULL;
-		res = g_ptr_array_index (results, i);
+		FwupdResult *res = g_ptr_array_index (results, i);
 		tmp = fwupd_result_to_string (res);
 		g_print ("%s\n", tmp);
 	}
@@ -302,7 +292,6 @@ fu_util_install (FuUtilPrivate *priv, gchar **values, GError **error)
 static gboolean
 fu_util_get_details (FuUtilPrivate *priv, gchar **values, GError **error)
 {
-	guint i;
 	g_autoptr(GPtrArray) array = NULL;
 
 	/* check args */
@@ -316,7 +305,7 @@ fu_util_get_details (FuUtilPrivate *priv, gchar **values, GError **error)
 	array = fwupd_client_get_details_local (priv->client, values[0], NULL, error);
 	if (array == NULL)
 		return FALSE;
-	for (i = 0; i < array->len; i++) {
+	for (guint i = 0; i < array->len; i++) {
 		FwupdResult *res = g_ptr_array_index (array, i);
 		g_autofree gchar *tmp = NULL;
 		tmp = fwupd_result_to_string (res);
@@ -356,7 +345,6 @@ fu_util_install_prepared (FuUtilPrivate *priv, gchar **values, GError **error)
 {
 	gint vercmp;
 	guint cnt = 0;
-	guint i;
 	g_autofree gchar *link = NULL;
 	g_autoptr(GPtrArray) results = NULL;
 	g_autoptr(FuPending) pending = NULL;
@@ -399,9 +387,8 @@ fu_util_install_prepared (FuUtilPrivate *priv, gchar **values, GError **error)
 		return FALSE;
 
 	/* apply each update */
-	for (i = 0; i < results->len; i++) {
-		FwupdResult *res;
-		res = g_ptr_array_index (results, i);
+	for (guint i = 0; i < results->len; i++) {
+		FwupdResult *res = g_ptr_array_index (results, i);
 
 		/* check not already done */
 		if (fwupd_result_get_update_state (res) != FWUPD_UPDATE_STATE_PENDING)
@@ -476,8 +463,6 @@ fu_util_clear_results (FuUtilPrivate *priv, gchar **values, GError **error)
 static gboolean
 fu_util_dump_rom (FuUtilPrivate *priv, gchar **values, GError **error)
 {
-	guint i;
-
 	if (g_strv_length (values) == 0) {
 		g_set_error_literal (error,
 				     FWUPD_ERROR,
@@ -485,7 +470,7 @@ fu_util_dump_rom (FuUtilPrivate *priv, gchar **values, GError **error)
 				     "Invalid arguments: expected 'filename.rom'");
 		return FALSE;
 	}
-	for (i = 0; values[i] != NULL; i++) {
+	for (guint i = 0; values[i] != NULL; i++) {
 		g_autoptr(FuRom) rom = NULL;
 		g_autoptr(GFile) file = NULL;
 		g_autoptr(GError) error_local = NULL;
@@ -513,7 +498,6 @@ fu_util_verify_update_internal (FuUtilPrivate *priv,
 				gchar **values,
 				GError **error)
 {
-	guint i;
 	g_autoptr(AsStore) store = NULL;
 	g_autoptr(GFile) xml_file = NULL;
 
@@ -528,7 +512,7 @@ fu_util_verify_update_internal (FuUtilPrivate *priv,
 
 	/* add new values */
 	as_store_set_api_version (store, 0.9);
-	for (i = 0; values[i] != NULL; i++) {
+	for (guint i = 0; values[i] != NULL; i++) {
 		g_autofree gchar *id = NULL;
 		g_autoptr(AsApp) app = NULL;
 		g_autoptr(AsChecksum) csum = NULL;
@@ -581,22 +565,19 @@ fu_util_verify_update_internal (FuUtilPrivate *priv,
 static gboolean
 fu_util_verify_update_all (FuUtilPrivate *priv, const gchar *fn, GError **error)
 {
-	GList *devices;
-	GList *l;
 	GUdevDevice *dev;
 	const gchar *devclass[] = { "pci", NULL };
 	const gchar *subsystems[] = { NULL };
-	guint i;
 	g_autoptr(GUdevClient) gudev_client = NULL;
 	g_autoptr(GPtrArray) roms = NULL;
 
 	/* get all devices of class */
 	gudev_client = g_udev_client_new (subsystems);
 	roms = g_ptr_array_new_with_free_func (g_free);
-	for (i = 0; devclass[i] != NULL; i++) {
-		devices = g_udev_client_query_by_subsystem (gudev_client,
+	for (guint i = 0; devclass[i] != NULL; i++) {
+		GList *devices = g_udev_client_query_by_subsystem (gudev_client,
 							    devclass[i]);
-		for (l = devices; l != NULL; l = l->next) {
+		for (GList *l = devices; l != NULL; l = l->next) {
 			g_autofree gchar *rom_fn = NULL;
 			dev = l->data;
 			rom_fn = g_build_filename (g_udev_device_get_sysfs_path (dev), "rom", NULL);
@@ -805,8 +786,6 @@ fu_util_get_results (FuUtilPrivate *priv, gchar **values, GError **error)
 static gboolean
 fu_util_verify_all (FuUtilPrivate *priv, GError **error)
 {
-	FwupdResult *res;
-	guint i;
 	g_autoptr(GPtrArray) results = NULL;
 
 	/* get devices from daemon */
@@ -815,9 +794,9 @@ fu_util_verify_all (FuUtilPrivate *priv, GError **error)
 		return FALSE;
 
 	/* get results */
-	for (i = 0; i < results->len; i++) {
+	for (guint i = 0; i < results->len; i++) {
 		g_autoptr(GError) error_local = NULL;
-		res = g_ptr_array_index (results, i);
+		FwupdResult *res = g_ptr_array_index (results, i);
 		if (!fwupd_client_verify (priv->client,
 					  fwupd_result_get_device_id (res),
 					  NULL,
@@ -865,8 +844,6 @@ fu_util_unlock (FuUtilPrivate *priv, gchar **values, GError **error)
 static void
 fu_util_print_data (const gchar *title, const gchar *msg)
 {
-	guint i;
-	guint j;
 	guint title_len;
 	g_auto(GStrv) lines = NULL;
 
@@ -877,8 +854,8 @@ fu_util_print_data (const gchar *title, const gchar *msg)
 	/* pad */
 	title_len = strlen (title) + 1;
 	lines = g_strsplit (msg, "\n", -1);
-	for (j = 0; lines[j] != NULL; j++) {
-		for (i = title_len; i < 25; i++)
+	for (guint j = 0; lines[j] != NULL; j++) {
+		for (guint i = title_len; i < 25; i++)
 			g_print (" ");
 		g_print ("%s\n", lines[j]);
 		title_len = 0;
@@ -902,19 +879,17 @@ _g_checksum_type_to_string (GChecksumType checksum_type)
 static gboolean
 fu_util_get_updates (FuUtilPrivate *priv, gchar **values, GError **error)
 {
-	FwupdResult *res;
 	GPtrArray *results = NULL;
 	GPtrArray *guids;
 	GChecksumType checksum_type;
 	const gchar *tmp;
-	guint i, j;
 
 	/* print any updates */
 	results = fwupd_client_get_updates (priv->client, NULL, error);
 	if (results == NULL)
 		return FALSE;
-	for (i = 0; i < results->len; i++) {
-		res = g_ptr_array_index (results, i);
+	for (guint i = 0; i < results->len; i++) {
+		FwupdResult *res = g_ptr_array_index (results, i);
 
 		/* TRANSLATORS: first replacement is device name */
 		g_print (_("%s has firmware updates:"), fwupd_result_get_device_name (res));
@@ -925,7 +900,7 @@ fu_util_get_updates (FuUtilPrivate *priv, gchar **values, GError **error)
 
 		/* TRANSLATORS: a GUID for the hardware */
 		guids = fwupd_result_get_guids (res);
-		for (j = 0; j < guids->len; j++) {
+		for (guint j = 0; j < guids->len; j++) {
 			tmp = g_ptr_array_index (guids, j);
 			fu_util_print_data (_("GUID"), tmp);
 		}
@@ -1039,22 +1014,20 @@ fu_util_monitor (FuUtilPrivate *priv, gchar **values, GError **error)
 static gboolean
 fu_util_update (FuUtilPrivate *priv, gchar **values, GError **error)
 {
-	FwupdResult *res;
 	GPtrArray *results = NULL;
-	guint i;
 
 	/* apply any updates */
 	results = fwupd_client_get_updates (priv->client, NULL, error);
 	if (results == NULL)
 		return FALSE;
-	for (i = 0; i < results->len; i++) {
+	for (guint i = 0; i < results->len; i++) {
 		GChecksumType checksum_type;
 		const gchar *checksum;
 		const gchar *uri;
 		g_autofree gchar *basename = NULL;
 		g_autofree gchar *fn = NULL;
 
-		res = g_ptr_array_index (results, i);
+		FwupdResult *res = g_ptr_array_index (results, i);
 
 		/* download file */
 		checksum = fwupd_result_get_update_checksum (res);