diff --git a/ampel-firmware/wifi_util.cpp b/ampel-firmware/wifi_util.cpp
index dc496293345f5b3f743e6ed369d5e792376514d9..8f81140c67715304adc2ff6bc8cb1b8a3877e4b9 100644
--- a/ampel-firmware/wifi_util.cpp
+++ b/ampel-firmware/wifi_util.cpp
@@ -13,14 +13,14 @@ namespace config {
 }
 
 // Initialize Wi-Fi
-void WiFiConnect(const String &hostname) {
+void WiFiConnect(const char *hostname) {
   //NOTE: WiFi Multi could allow multiple SSID and passwords.
   WiFi.persistent(false); // Don't write user & password to Flash.
   WiFi.mode(WIFI_STA); // Set ESP to be a WiFi-client only
 #if defined(ESP8266)
     WiFi.hostname(hostname);
 #elif defined(ESP32)
-  WiFi.setHostname(hostname.c_str());
+  WiFi.setHostname(hostname);
 #endif
 
   Serial.print(F("WiFi - Connecting to "));
diff --git a/ampel-firmware/wifi_util.h b/ampel-firmware/wifi_util.h
index 7520ed78e070cf552500441f4828bb7d339392b8..e6c8635ab545e1e7995613901b84b17bab7752e2 100644
--- a/ampel-firmware/wifi_util.h
+++ b/ampel-firmware/wifi_util.h
@@ -5,6 +5,6 @@
 #include "util.h"
 #include "led_effects.h"
 
-void WiFiConnect(const String &hostname);
+void WiFiConnect(const char *hostname);
 
 #endif