diff --git a/message_generation/src/main/java/org/ros/internal/message/field/ChannelBufferField.java b/message_generation/src/main/java/org/ros/internal/message/field/ChannelBufferField.java
index a13f5425..696131ae 100644
--- a/message_generation/src/main/java/org/ros/internal/message/field/ChannelBufferField.java
+++ b/message_generation/src/main/java/org/ros/internal/message/field/ChannelBufferField.java
@@ -64,7 +64,7 @@ public void serialize(ChannelBuffer buffer) {
     }
     // By specifying the start index and length we avoid modifying value's
     // indices and marks.
-    buffer.writeBytes(value, 0, value.readableBytes());
+    buffer.writeBytes(value, 0, Math.max(value.readableBytes(), size));
   }
 
   @Override