diff --git a/AMWD.Protocols.Modbus.Serial/ModbusRtuProxy.cs b/AMWD.Protocols.Modbus.Serial/ModbusRtuProxy.cs
index 3670006..3070dc4 100644
--- a/AMWD.Protocols.Modbus.Serial/ModbusRtuProxy.cs
+++ b/AMWD.Protocols.Modbus.Serial/ModbusRtuProxy.cs
@@ -738,8 +738,9 @@ namespace AMWD.Protocols.Modbus.Serial
 
 					byte[] objBytes = GetDeviceObject((byte)i, deviceInfo);
 
-					// We need to split the response if it would exceed the max ADU size
-					if (responseBytes.Count + bodyBytes.Count + objBytes.Length > RtuProtocol.MAX_ADU_LENGTH)
+					// We need to split the response if it would exceed the max ADU size.
+					// 2 bytes of CRC have to be added.
+					if (responseBytes.Count + bodyBytes.Count + objBytes.Length + 2 > RtuProtocol.MAX_ADU_LENGTH)
 					{
 						bodyBytes[3] = 0xFF;
 						bodyBytes[4] = (byte)i;
@@ -831,9 +832,8 @@ namespace AMWD.Protocols.Modbus.Serial
 
 				default:
 					{
-						if (deviceIdentification.ExtendedObjects.ContainsKey(objectId))
+						if (deviceIdentification.ExtendedObjects.TryGetValue(objectId, out byte[] bytes))
 						{
-							byte[] bytes = deviceIdentification.ExtendedObjects[objectId];
 							result.Add((byte)bytes.Length);
 							result.AddRange(bytes);
 						}
diff --git a/AMWD.Protocols.Modbus.Tests/Serial/ModbusRtuProxyTest.cs b/AMWD.Protocols.Modbus.Tests/Serial/ModbusRtuProxyTest.cs
index cc7a3b3..99373f2 100644
--- a/AMWD.Protocols.Modbus.Tests/Serial/ModbusRtuProxyTest.cs
+++ b/AMWD.Protocols.Modbus.Tests/Serial/ModbusRtuProxyTest.cs
@@ -1050,14 +1050,21 @@ namespace AMWD.Protocols.Modbus.Tests.Serial
 			_requestBytesQueue.Enqueue([.. request, .. RtuProtocol.CRC16(request)]);
 			byte[] expectedResponse = [
 				1, 43, 14, 3,
-				3, 255, 224, 103,
+				3, 255, 223, 102,
 				0, 10, 86, 101, 110, 100, 111, 114, 78, 97, 109, 101,
 				1, 11, 80, 114, 111, 100, 117, 99, 116, 67, 111, 100, 101,
 				2, 18, 77, 97, 106, 111, 114, 77, 105, 110, 111, 114, 82, 101, 118, 105, 115, 105, 111, 110,
 				3, 0, 4, 0, 5, 0, 6, 0,
 				128, 0, 129, 0, 130, 0,
 				131, 3, 11, 22, 33,
-				132, 0, 133, 0, 134, 0, 135, 0, 136, 0, 137, 0, 138, 0, 139, 0, 140, 0, 141, 0, 142, 0, 143, 0, 144, 0, 145, 0, 146, 0, 147, 0, 148, 0, 149, 0, 150, 0, 151, 0, 152, 0, 153, 0, 154, 0, 155, 0, 156, 0, 157, 0, 158, 0, 159, 0, 160, 0, 161, 0, 162, 0, 163, 0, 164, 0, 165, 0, 166, 0, 167, 0, 168, 0, 169, 0, 170, 0, 171, 0, 172, 0, 173, 0, 174, 0, 175, 0, 176, 0, 177, 0, 178, 0, 179, 0, 180, 0, 181, 0, 182, 0, 183, 0, 184, 0, 185, 0, 186, 0, 187, 0, 188, 0, 189, 0, 190, 0, 191, 0, 192, 0, 193, 0, 194, 0, 195, 0, 196, 0, 197, 0, 198, 0, 199, 0, 200, 0, 201, 0, 202, 0, 203, 0, 204, 0, 205, 0, 206, 0, 207, 0, 208, 0, 209, 0, 210, 0, 211, 0, 212, 0, 213, 0, 214, 0, 215, 0, 216, 0, 217, 0, 218, 0, 219, 0, 220, 0, 221, 0, 222, 0, 223, 0];
+				132, 0, 133, 0, 134, 0, 135, 0, 136, 0, 137, 0, 138, 0, 139, 0, 140, 0, 141, 0, 142, 0, 143, 0,
+				144, 0, 145, 0, 146, 0, 147, 0, 148, 0, 149, 0, 150, 0, 151, 0, 152, 0, 153, 0, 154, 0, 155, 0,
+				156, 0, 157, 0, 158, 0, 159, 0, 160, 0, 161, 0, 162, 0, 163, 0, 164, 0, 165, 0, 166, 0, 167, 0,
+				168, 0, 169, 0, 170, 0, 171, 0, 172, 0, 173, 0, 174, 0, 175, 0, 176, 0, 177, 0, 178, 0, 179, 0,
+				180, 0, 181, 0, 182, 0, 183, 0, 184, 0, 185, 0, 186, 0, 187, 0, 188, 0, 189, 0, 190, 0, 191, 0,
+				192, 0, 193, 0, 194, 0, 195, 0, 196, 0, 197, 0, 198, 0, 199, 0, 200, 0, 201, 0, 202, 0, 203, 0,
+				204, 0, 205, 0, 206, 0, 207, 0, 208, 0, 209, 0, 210, 0, 211, 0, 212, 0, 213, 0, 214, 0, 215, 0,
+				216, 0, 217, 0, 218, 0, 219, 0, 220, 0, 221, 0, 222, 0];
 
 			using var proxy = GetProxy();
 			await proxy.StartAsync();
@@ -1072,7 +1079,7 @@ namespace AMWD.Protocols.Modbus.Tests.Serial
 			_serialPortMock.Verify(m => m.Close(), Times.Once);
 			_serialPortMock.Verify(m => m.Open(), Times.Once);
 			_serialPortMock.Verify(m => m.Read(It.IsAny<byte[]>(), 0, RtuProtocol.MAX_ADU_LENGTH), Times.Once);
-			_serialPortMock.Verify(m => m.Write(It.IsAny<byte[]>(), 0, 258), Times.Once);
+			_serialPortMock.Verify(m => m.Write(It.IsAny<byte[]>(), 0, 256), Times.Once);
 
 			_serialPortMock.VerifyAdd(m => m.DataReceived += It.IsAny<SerialDataReceivedEventHandler>(), Times.Once);
 			_serialPortMock.VerifyRemove(m => m.DataReceived -= It.IsAny<SerialDataReceivedEventHandler>(), Times.Once);