diff --git a/index.js b/index.js
index d175395..396a595 100644
--- a/index.js
+++ b/index.js
@@ -44,6 +44,7 @@ rm4DeviceTypes[parseInt(0x6070, 16)] = "Broadlink RM4 Mini C";
 rm4DeviceTypes[parseInt(0x62be, 16)] = "Broadlink RM4 Mini C";
 rm4DeviceTypes[parseInt(0x610f, 16)] = "Broadlink RM4 Mini C";
 rm4DeviceTypes[parseInt(0x6539, 16)] = "Broadlink RM4 Mini C";
+rm4DeviceTypes[parseInt(0x520d, 16)] = "Broadlink RM4 Mini C";
 rm4DeviceTypes[parseInt(0x648d, 16)] = "Broadlink RM4 Mini S";
 rm4DeviceTypes[parseInt(0x5216, 16)] = "Broadlink RM4 Mini";
 rm4DeviceTypes[parseInt(0x520c, 16)] = "Broadlink RM4 Mini";
@@ -216,7 +217,7 @@ class Broadlink extends EventEmitter {
   addDevice (host, macAddress, deviceType) {
     const { log, debug } = this;
 
-    if (this.devices[macAddress]) return;
+    if (this.devices[macAddress.toString('hex')]) return;
 
     const isHostObjectValid = (
       typeof host === 'object' &&
@@ -230,7 +231,7 @@ class Broadlink extends EventEmitter {
 
     // Mark is at not supported by default so we don't try to
     // create this device again.
-    this.devices[macAddress] = 'Not Supported';
+    this.devices[macAddress.toString('hex')] = 'Not Supported';
 
     // Ignore devices that don't support infrared or RF.
     if (unsupportedDeviceTypes[parseInt(deviceType, 16)]) return null;
@@ -251,7 +252,7 @@ class Broadlink extends EventEmitter {
     device.log = log;
     device.debug = debug;
 
-    this.devices[macAddress] = device;
+    this.devices[macAddress.toString('hex')] = device;
 
     // Authenticate the device and let others know when it's ready.
     device.on('deviceReady', () => {
diff --git a/package.json b/package.json
index 34f997f..f3d26a4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "kiwicam-broadlinkjs-rm",
-  "version": "0.9.20-beta.0",
+  "version": "0.9.20-beta.1",
   "description": "A Node.JS fork of broadlinkjs specifically intended for interacting with RM devices in homebridge-broadlink-rm",
   "main": "index.js",
   "scripts": {