diff --git a/ampel-firmware/ampel-firmware.ino b/ampel-firmware/ampel-firmware.ino
index c5e82c868a13ce2eca3fd5365e9364c903a50d52..00a8986511a6f49924a233e157c21d754070afe2 100644
--- a/ampel-firmware/ampel-firmware.ino
+++ b/ampel-firmware/ampel-firmware.ino
@@ -55,6 +55,19 @@
  * and define your credentials and parameters in 'config.h'.
  */
 
+
+/*****************************************************************
+ * PreInit                                                       *
+ *****************************************************************/
+void preinit() {
+#if !defined(AMPEL_WIFI) && defined(ESP8266)
+  // WiFi would be initialized otherwise (on ESP8266), even if unused.
+  // see https://github.com/esp8266/Arduino/issues/2111#issuecomment-224251391
+  ESP8266WiFiClass::preinitWiFiOff();
+#endif
+}
+
+
 /*****************************************************************
  * Setup                                                         *
  *****************************************************************/