Edits to README.md detailing drivers necessary for flashing on Macs

code/README.md

@@ -21,6 +21,8 @@ This will create a virtual Python environment and install two essential tools:
 [esptool](https://github.com/espressif/esptool), used for flashing firmware to the device, and
 [ampy](https://github.com/adafruit/ampy), used to manipulate the filesystem.
 
+The Wemos D1 mini requires a driver for Mac OS X to drive the CH340 serial bridge. It can be downloaded [here](https://blog.sengotta.net/signed-mac-os-driver-for-winchiphead-ch340-serial-bridge/).
+
 ### Preparing the ESP8266
 
 1. Connect the ESP8266 module to your computer and determine its serial port identifier.