diff --git a/examples/FirebaseRoom_ESP8266/README.md b/examples/FirebaseRoom_ESP8266/README.md
index a939d1c2..0d863a03 100644
--- a/examples/FirebaseRoom_ESP8266/README.md
+++ b/examples/FirebaseRoom_ESP8266/README.md
@@ -7,6 +7,7 @@ sensor data to Firebase, and trigger actuators from Firebase.
 
 1. Install [Arduino 1.6.9](https://www.arduino.cc/en/Main/Software)
 1. Install [Arduino ESP8266 core](https://github.com/esp8266/Arduino#installing-with-boards-manager)
+1. Install [Silicon Labs VCP driver](https://www.silabs.com/products/mcu/Pages/USBtoUARTBridgeVCPDrivers.aspx) (OS X only)
 1. Download [FirebaseArduino library](https://github.com/googlesamples/firebase-arduino/archive/master.zip)
 1. Start Arduino
 1. Click `Sketch > Include Library > Add .ZIP Library...`