diff --git a/Documentation/reference/os/iob.rst b/Documentation/reference/os/iob.rst
index ecb925dc9f..5249139a87 100644
--- a/Documentation/reference/os/iob.rst
+++ b/Documentation/reference/os/iob.rst
@@ -267,7 +267,8 @@ Public Function Prototypes
   buffer starting at ``offset`` in the I/O buffer, returning that
   actual number of bytes copied out.
 
-.. c:function:: int iob_clone(FAR struct iob_s *iob1, FAR struct iob_s *iob2, bool throttled)
+.. c:function:: int iob_clone(FAR struct iob_s *iob1, FAR struct iob_s *iob2, \
+                   bool throttled, bool block);
 
   Duplicate (and pack) the data in ``iob1`` in
   ``iob2``. ``iob2`` must be empty.
diff --git a/include/nuttx/mm/iob.h b/include/nuttx/mm/iob.h
index fa672d0cd5..7ced19a487 100644
--- a/include/nuttx/mm/iob.h
+++ b/include/nuttx/mm/iob.h
@@ -464,8 +464,8 @@ unsigned int iob_tailroom(FAR struct iob_s *iob);
  *
  ****************************************************************************/
 
-int iob_clone(FAR struct iob_s *iob1,
-              FAR struct iob_s *iob2, bool throttled);
+int iob_clone(FAR struct iob_s *iob1, FAR struct iob_s *iob2,
+              bool throttled, bool block);
 
 /****************************************************************************
  * Name: iob_concat
diff --git a/mm/iob/iob_clone.c b/mm/iob/iob_clone.c
index 1a149bd059..8184d3b3d4 100644
--- a/mm/iob/iob_clone.c
+++ b/mm/iob/iob_clone.c
@@ -53,7 +53,8 @@
  *
  ****************************************************************************/
 
-int iob_clone(FAR struct iob_s *iob1, FAR struct iob_s *iob2, bool throttled)
+int iob_clone(FAR struct iob_s *iob1, FAR struct iob_s *iob2,
+              bool throttled, bool block)
 {
   FAR uint8_t *src;
   FAR uint8_t *dest;
@@ -145,7 +146,15 @@ int iob_clone(FAR struct iob_s *iob1, FAR struct iob_s *iob2, bool throttled)
            * destination I/O buffer chain.
            */
 
-          next = iob_alloc(throttled);
+          if (block)
+            {
+              next = iob_alloc(throttled);
+            }
+          else
+            {
+              next = iob_tryalloc(throttled);
+            }
+
           if (!next)
             {
               ioberr("ERROR: Failed to allocate an I/O buffer\n");