diff --git a/cores/esp8266/i2s.h b/cores/esp8266/i2s.h
deleted file mode 100644
index e3d40706c..000000000
--- a/cores/esp8266/i2s.h
+++ /dev/null
@@ -1,12 +0,0 @@
-// This include file is a hack to ensure backward compatibility with
-// pre 3.0.0 versions of the core.  There was a *lowercase* "i2s.h"
-// header which was in this directory, now renamed to "core_esp82i66s.h"
-// But, the I2S class has a header, "I2S.h" in uppercase.  On Linux
-// the two names are different, but on Windows it's case-insensitive
-// so the names conflict.
-//
-// Avoid the issue by preserving the old i2s.h file and have it redirect
-// to I2S.h which will give the ESP8266-specific functions as well as
-// the generic I2S class.
-
-#include "../../libraries/I2S/src/I2S.h"
diff --git a/libraries/esp8266/examples/I2SInput/I2SInput.ino b/libraries/esp8266/examples/I2SInput/I2SInput.ino
index 0f1ba7e43..836da2685 100644
--- a/libraries/esp8266/examples/I2SInput/I2SInput.ino
+++ b/libraries/esp8266/examples/I2SInput/I2SInput.ino
@@ -28,7 +28,7 @@
 */
 
 #include <ESP8266WiFi.h>
-#include <i2s.h>
+#include <I2S.h>
 
 void setup() {
   Serial.begin(115200);
diff --git a/libraries/esp8266/examples/I2STransmit/I2STransmit.ino b/libraries/esp8266/examples/I2STransmit/I2STransmit.ino
index 0c7a7eb43..02121d2bf 100644
--- a/libraries/esp8266/examples/I2STransmit/I2STransmit.ino
+++ b/libraries/esp8266/examples/I2STransmit/I2STransmit.ino
@@ -10,7 +10,7 @@
 
 #include <ESP8266WiFi.h>
 #include <WiFiUdp.h>
-#include <i2s.h>
+#include <I2S.h>
 
 #ifndef STASSID
 #define STASSID "your-ssid"