diff --git a/src/as/com/threerings/io/ObjectInputStream.as b/src/as/com/threerings/io/ObjectInputStream.as
index 1a9c81b6f..8d910a108 100644
--- a/src/as/com/threerings/io/ObjectInputStream.as
+++ b/src/as/com/threerings/io/ObjectInputStream.as
@@ -202,8 +202,7 @@ public class ObjectInputStream
      * Read bytes into the byte array. If length is not specified, then
      * enough bytes to fill the array (from the offset) are read.
      */
-    public function readBytes (bytes :ByteArray, offset :uint = 0,
-            length :int = -1) :void
+    public function readBytes (bytes :ByteArray, offset :int = 0, length :int = -1) :void
         //throws IOError
     {
         // if no length specified then fill the ByteArray
diff --git a/src/as/com/threerings/io/ObjectOutputStream.as b/src/as/com/threerings/io/ObjectOutputStream.as
index a8cbb9d60..0901c01b7 100644
--- a/src/as/com/threerings/io/ObjectOutputStream.as
+++ b/src/as/com/threerings/io/ObjectOutputStream.as
@@ -164,11 +164,15 @@ public class ObjectOutputStream
         _targ.writeByte(value);
     }
 
-    public function writeBytes (bytes :ByteArray, offset :uint=0,
-            length :uint = 0) :void
+    public function writeBytes (bytes :ByteArray, offset :int = 0, length :int = -1) :void
         //throws IOError
     {
-        _targ.writeBytes(bytes, offset, length);
+        if (length == -1) {
+            length = bytes.length - offset;
+        }
+        if (length > 0) {
+            _targ.writeBytes(bytes, offset, length);
+        }
     }
 
     public function writeDouble (value :Number) :void