diff --git a/tasmota/xdrv_28_pcf8574.ino b/tasmota/xdrv_28_pcf8574.ino
index 93e8d825d..b79f3caa6 100644
--- a/tasmota/xdrv_28_pcf8574.ino
+++ b/tasmota/xdrv_28_pcf8574.ino
@@ -168,7 +168,7 @@ void HandlePcf8574(void)
 
   WSContentStart_P(D_CONFIGURE_PCF8574);
   WSContentSendStyle();
-  WSContentSend_P(HTTP_FORM_I2C_PCF8574_1, (Settings.flag3.pcf8574_ports_inverted) ? PST(" checked") : "");  // SetOption81 - Invert all ports on PCF8574 devices
+  WSContentSend_P(HTTP_FORM_I2C_PCF8574_1, (Settings.flag3.pcf8574_ports_inverted) ? PSTR(" checked") : "");  // SetOption81 - Invert all ports on PCF8574 devices
   WSContentSend_P(HTTP_TABLE100);
   for (uint32_t idx = 0; idx < Pcf8574.max_devices; idx++) {
     for (uint32_t idx2 = 0; idx2 < 8; idx2++) {  // 8 ports on PCF8574