diff --git a/libfwupdplugin/fu-context.c b/libfwupdplugin/fu-context.c
index 1b0df08d9..cf16c0ca3 100644
--- a/libfwupdplugin/fu-context.c
+++ b/libfwupdplugin/fu-context.c
@@ -454,7 +454,10 @@ const gchar *
 fu_context_lookup_quirk_by_id (FuContext *self, const gchar *guid, const gchar *key)
 {
 	FuContextPrivate *priv = GET_PRIVATE (self);
+
 	g_return_val_if_fail (FU_IS_CONTEXT (self), NULL);
+	g_return_val_if_fail (guid != NULL, NULL);
+	g_return_val_if_fail (key != NULL, NULL);
 
 	/* exact ID */
 	return fu_quirks_lookup_by_id (priv->quirks, guid, key);
diff --git a/plugins/upower/fu-plugin-upower.c b/plugins/upower/fu-plugin-upower.c
index 5fa5caa0d..6ff2e7a6f 100644
--- a/plugins/upower/fu-plugin-upower.c
+++ b/plugins/upower/fu-plugin-upower.c
@@ -113,9 +113,11 @@ fu_plugin_startup (FuPlugin *plugin, GError **error)
 		const gchar *vendor = fu_context_get_hwid_replace_value (ctx,
 									 FU_HWIDS_KEY_MANUFACTURER,
 									 NULL);
-		battery_str = g_strdup (fu_context_lookup_quirk_by_id (ctx,
-								       vendor,
-								       FU_QUIRKS_BATTERY_THRESHOLD));
+		if (vendor != NULL) {
+			battery_str = g_strdup (fu_context_lookup_quirk_by_id (ctx,
+									       vendor,
+									       FU_QUIRKS_BATTERY_THRESHOLD));
+		}
 	}
 	if (battery_str == NULL)
 		minimum_battery = MINIMUM_BATTERY_PERCENTAGE_FALLBACK;