=== modified file 'grub-core/bus/usb/serial/ftdi.c'
--- grub-core/bus/usb/serial/ftdi.c	2013-02-01 20:49:29 +0000
+++ grub-core/bus/usb/serial/ftdi.c	2013-02-24 18:58:04 +0000
@@ -128,7 +128,7 @@
 
   real_config (port);
 
-  grub_usb_bulk_write (port->usbdev, port->out_endp->endp_addr, 1, &cc);
+  grub_usb_bulk_write (port->usbdev, port->out_endp, 1, &cc);
 }
 
 static grub_err_t

=== modified file 'grub-core/bus/usb/serial/pl2303.c'
--- grub-core/bus/usb/serial/pl2303.c	2013-02-01 20:49:29 +0000
+++ grub-core/bus/usb/serial/pl2303.c	2013-02-24 18:57:48 +0000
@@ -146,7 +146,7 @@
 
   real_config (port);
 
-  grub_usb_bulk_write (port->usbdev, port->out_endp->endp_addr, 1, &cc);
+  grub_usb_bulk_write (port->usbdev, port->out_endp, 1, &cc);
 }
 
 static grub_err_t

=== modified file 'grub-core/bus/usb/serial/usbdebug_late.c'
--- grub-core/bus/usb/serial/usbdebug_late.c	2013-02-01 20:49:29 +0000
+++ grub-core/bus/usb/serial/usbdebug_late.c	2013-02-24 18:57:54 +0000
@@ -41,7 +41,7 @@
 {
   char cc = c;
 
-  grub_usb_bulk_write (port->usbdev, port->out_endp->endp_addr, 1, &cc);
+  grub_usb_bulk_write (port->usbdev, port->out_endp, 1, &cc);
 }
 
 static grub_err_t

=== modified file 'grub-core/bus/usb/usbtrans.c'
--- grub-core/bus/usb/usbtrans.c	2013-01-20 21:45:53 +0000
+++ grub-core/bus/usb/usbtrans.c	2013-02-24 18:57:19 +0000
@@ -333,38 +333,27 @@
   return err;
 }
 
-grub_usb_err_t
-grub_usb_bulk_write (grub_usb_device_t dev,
-		     int endpoint, grub_size_t size, char *data)
-{
-  grub_size_t actual;
-  grub_usb_err_t err;
-
-  err = grub_usb_bulk_readwrite (dev, endpoint, size, data,
-				 GRUB_USB_TRANSFER_TYPE_OUT, 1000, &actual);
-  if (!err && actual != size)
-    err = GRUB_USB_ERR_DATA;
-  return err;
-}
-
-grub_usb_err_t
-grub_usb_bulk_read (grub_usb_device_t dev,
-		    int endpoint, grub_size_t size, char *data)
+static grub_usb_err_t
+grub_usb_bulk_readwrite_packetize (grub_usb_device_t dev,
+				   struct grub_usb_desc_endp *endpoint,
+				   grub_transfer_type_t type,
+				   grub_size_t size, char *data)
 {
   grub_size_t actual, transferred;
   grub_usb_err_t err;
   grub_size_t current_size, position;
+  grub_size_t max_packet = endpoint->maxpacket;
 
   for (position = 0, transferred = 0;
-       position < size; position += MAX_USB_TRANSFER_LEN)
+       position < size; position += max_packet)
     {
       current_size = size - position;
-      if (current_size >= MAX_USB_TRANSFER_LEN)
-	current_size = MAX_USB_TRANSFER_LEN;
-      err = grub_usb_bulk_readwrite (dev, endpoint, current_size,
-              &data[position], GRUB_USB_TRANSFER_TYPE_IN, 1000, &actual);
+      if (current_size >= max_packet)
+	current_size = max_packet;
+      err = grub_usb_bulk_readwrite (dev, endpoint->endp_addr, current_size,
+              &data[position], type, 1000, &actual);
       transferred += actual;
-      if (err || (current_size != actual) ) break;
+      if (err || (current_size != actual)) break;
     }
 
   if (!err && transferred != size)
@@ -373,6 +362,26 @@
 }
 
 grub_usb_err_t
+grub_usb_bulk_read (grub_usb_device_t dev,
+		    struct grub_usb_desc_endp *endpoint,
+		    grub_size_t size, char *data)
+{
+  return grub_usb_bulk_readwrite_packetize (dev, endpoint,
+					    GRUB_USB_TRANSFER_TYPE_IN,
+					    size, data);
+}
+
+grub_usb_err_t
+grub_usb_bulk_write (grub_usb_device_t dev,
+		     struct grub_usb_desc_endp *endpoint,
+		     grub_size_t size, char *data)
+{
+  return grub_usb_bulk_readwrite_packetize (dev, endpoint,
+					    GRUB_USB_TRANSFER_TYPE_OUT,
+					    size, data);
+}
+
+grub_usb_err_t
 grub_usb_check_transfer (grub_usb_transfer_t transfer, grub_size_t *actual)
 {
   grub_usb_err_t err;

=== modified file 'grub-core/disk/usbms.c'
--- grub-core/disk/usbms.c	2013-01-20 15:52:15 +0000
+++ grub-core/disk/usbms.c	2013-02-24 18:56:43 +0000
@@ -326,7 +326,7 @@
 
   /* Write the request.
    * XXX: Error recovery is maybe still not fully correct. */
-  err = grub_usb_bulk_write (dev->dev, dev->out->endp_addr,
+  err = grub_usb_bulk_write (dev->dev, dev->out,
 			     sizeof (cbw), (char *) &cbw);
   if (err)
     {
@@ -341,7 +341,7 @@
   /* Read/write the data, (maybe) according to specification.  */
   if (size && (read_write == 0))
     {
-      err = grub_usb_bulk_read (dev->dev, dev->in->endp_addr, size, buf);
+      err = grub_usb_bulk_read (dev->dev, dev->in, size, buf);
       grub_dprintf ("usb", "read: %d %d\n", err, GRUB_USB_ERR_STALL); 
       if (err)
         {
@@ -362,7 +362,7 @@
     }
   else if (size)
     {
-      err = grub_usb_bulk_write (dev->dev, dev->out->endp_addr, size, buf);
+      err = grub_usb_bulk_write (dev->dev, dev->out, size, buf);
       grub_dprintf ("usb", "write: %d %d\n", err, GRUB_USB_ERR_STALL);
       grub_dprintf ("usb", "First 16 bytes of sent data:\n %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
   	buf[ 0], buf[ 1], buf[ 2], buf[ 3],
@@ -388,12 +388,12 @@
 
   /* Read the status - (maybe) according to specification.  */
 CheckCSW:
-  errCSW = grub_usb_bulk_read (dev->dev, dev->in->endp_addr,
+  errCSW = grub_usb_bulk_read (dev->dev, dev->in,
 		    sizeof (status), (char *) &status);
   if (errCSW)
     {
       grub_usb_clear_halt (dev->dev, dev->in->endp_addr);
-      errCSW = grub_usb_bulk_read (dev->dev, dev->in->endp_addr,
+      errCSW = grub_usb_bulk_read (dev->dev, dev->in,
 			        sizeof (status), (char *) &status);
       if (errCSW)
         { /* Bulk-only reset device. */
@@ -476,7 +476,7 @@
       else if (dev->protocol == GRUB_USBMS_PROTOCOL_CBI)
         {
           /* Try to get status from interrupt pipe */
-          err = grub_usb_bulk_read (dev->dev, dev->intrpt->endp_addr,
+          err = grub_usb_bulk_read (dev->dev, dev->intrpt,
                                     2, (char*)&status);
           grub_dprintf ("usb", "CBI cmdcb setup status: err=%d, status=0x%x\n", err, status);
         }
@@ -487,7 +487,7 @@
   /* Read/write the data, (maybe) according to specification.  */
   if (size && (read_write == 0))
     {
-      err = grub_usb_bulk_read (dev->dev, dev->in->endp_addr, size, buf);
+      err = grub_usb_bulk_read (dev->dev, dev->in, size, buf);
       grub_dprintf ("usb", "read: %d\n", err); 
       if (err)
         {
@@ -498,7 +498,7 @@
     }
   else if (size)
     {
-      err = grub_usb_bulk_write (dev->dev, dev->out->endp_addr, size, buf);
+      err = grub_usb_bulk_write (dev->dev, dev->out, size, buf);
       grub_dprintf ("usb", "write: %d\n", err);
       if (err)
         {
@@ -517,7 +517,7 @@
    * (we do not it yet) - ? */
   if (dev->protocol == GRUB_USBMS_PROTOCOL_CBI)
     { /* Check status in interrupt pipe */
-      err = grub_usb_bulk_read (dev->dev, dev->intrpt->endp_addr,
+      err = grub_usb_bulk_read (dev->dev, dev->intrpt,
                                 2, (char*)&status);
       grub_dprintf ("usb", "read status: %d\n", err);
       if (err)

=== modified file 'include/grub/usb.h'
--- include/grub/usb.h	2013-01-21 21:02:24 +0000
+++ include/grub/usb.h	2013-02-24 18:47:19 +0000
@@ -87,10 +87,12 @@
 
 grub_usb_err_t
 grub_usb_bulk_read (grub_usb_device_t dev,
-		    int endpoint, grub_size_t size, char *data);
+		    struct grub_usb_desc_endp *endpoint,
+		    grub_size_t size, char *data);
 grub_usb_err_t
 grub_usb_bulk_write (grub_usb_device_t dev,
-		     int endpoint, grub_size_t size, char *data);
+		     struct grub_usb_desc_endp *endpoint,
+		     grub_size_t size, char *data);
 
 grub_usb_err_t
 grub_usb_root_hub (grub_usb_controller_t controller);

=== modified file 'include/grub/usbtrans.h'
--- include/grub/usbtrans.h	2013-01-20 21:45:53 +0000
+++ include/grub/usbtrans.h	2013-02-24 18:48:55 +0000
@@ -19,8 +19,6 @@
 #ifndef	GRUB_USBTRANS_H
 #define	GRUB_USBTRANS_H	1
 
-#define MAX_USB_TRANSFER_LEN 0x0800
-
 typedef enum
   {
     GRUB_USB_TRANSFER_TYPE_IN,