diff --git a/urjtag/ChangeLog b/urjtag/ChangeLog
index 65a2783f..b522b21e 100644
--- a/urjtag/ChangeLog
+++ b/urjtag/ChangeLog
@@ -1,3 +1,9 @@
+2010-02-02  Jie Zhang  <jie.zhang@analog.com>
+
+  * src/tap/usbconn/libftdi.c (usbconn_ftdi_write): Make sure
+    scheduled send bytes be less than URJ_USBCONN_FTDX_MAXSEND.
+  * src/tap/usbconn/libftd2xx.c (usbconn_ftd2xx_write): Likewise.
+
 2010-02-01  Jie Zhang  <jie.zhang@analog.com>
 
   * tap/cable/ft2232.c (ft2232_gnice_done): Turn LED off when done.
diff --git a/urjtag/src/tap/usbconn/libftd2xx.c b/urjtag/src/tap/usbconn/libftd2xx.c
index 38c96f5e..1407bed6 100644
--- a/urjtag/src/tap/usbconn/libftd2xx.c
+++ b/urjtag/src/tap/usbconn/libftd2xx.c
@@ -249,7 +249,7 @@ usbconn_ftd2xx_write (urj_usbconn_t *conn, uint8_t *buf, int len, int recv)
        with this write
        Case B: max number of scheduled send bytes has been reached */
     if ((p->to_recv + recv > URJ_USBCONN_FTD2XX_MAXRECV)
-        || ((p->send_buffered > URJ_USBCONN_FTDX_MAXSEND)
+        || ((p->send_buffered + len > URJ_USBCONN_FTDX_MAXSEND)
             && (p->to_recv == 0)))
         xferred = usbconn_ftd2xx_flush (p);
 
diff --git a/urjtag/src/tap/usbconn/libftdi.c b/urjtag/src/tap/usbconn/libftdi.c
index 86a2d9aa..34457d04 100644
--- a/urjtag/src/tap/usbconn/libftdi.c
+++ b/urjtag/src/tap/usbconn/libftdi.c
@@ -193,7 +193,7 @@ usbconn_ftdi_write (urj_usbconn_t *conn, uint8_t *buf, int len, int recv)
        with this write
        Case B: max number of scheduled send bytes has been reached */
     if ((p->to_recv + recv > URJ_USBCONN_FTDI_MAXRECV)
-        || ((p->send_buffered > URJ_USBCONN_FTDX_MAXSEND)
+        || ((p->send_buffered + len > URJ_USBCONN_FTDX_MAXSEND)
             && (p->to_recv == 0)))
         xferred = usbconn_ftdi_flush (p);