diff --git a/src/main/java/org/firmata4j/firmata/FirmataDevice.java b/src/main/java/org/firmata4j/firmata/FirmataDevice.java
index 591f0ea..cc3297c 100644
--- a/src/main/java/org/firmata4j/firmata/FirmataDevice.java
+++ b/src/main/java/org/firmata4j/firmata/FirmataDevice.java
@@ -518,7 +518,7 @@ public void accept(Event event) {
         @Override
         public void accept(Event event) {
             byte address = (Byte) event.getBodyItem(I2C_ADDRESS);
-            int register = (Integer) event.getBodyItem(I2C_REGISTER);
+            byte register = (Byte) event.getBodyItem(I2C_REGISTER);
             byte[] message = (byte[]) event.getBodyItem(I2C_MESSAGE);
             FirmataI2CDevice device = i2cDevices.get(address);
             if (device != null) {