diff -purB ./grub/grub-core/bus/usb/ehci.c ./grub_patched/grub-core/bus/usb/ehci.c
--- ./grub/grub-core/bus/usb/ehci.c	2013-01-27 22:12:17.000000000 +0100
+++ ./grub_patched/grub-core/bus/usb/ehci.c	2013-02-11 22:17:50.000000000 +0100
@@ -1902,7 +1897,9 @@ static struct grub_usb_controller_dev us
   .cancel_transfer = grub_ehci_cancel_transfer,
   .hubports = grub_ehci_hubports,
   .portstatus = grub_ehci_portstatus,
-  .detect_dev = grub_ehci_detect_dev
+  .detect_dev = grub_ehci_detect_dev,
+  /* estimated max. count of TDs for one bulk transfer */
+  .max_bulk_tds = GRUB_EHCI_N_TD * 3 / 4 
 };
 
 GRUB_MOD_INIT (ehci)
diff -purB ./grub/grub-core/bus/usb/ohci.c ./grub_patched/grub-core/bus/usb/ohci.c
--- ./grub/grub-core/bus/usb/ohci.c	2013-01-27 22:12:17.000000000 +0100
+++ ./grub_patched/grub-core/bus/usb/ohci.c	2013-02-11 22:28:55.000000000 +0100
@@ -1431,7 +1431,9 @@ static struct grub_usb_controller_dev us
   .cancel_transfer = grub_ohci_cancel_transfer,
   .hubports = grub_ohci_hubports,
   .portstatus = grub_ohci_portstatus,
-  .detect_dev = grub_ohci_detect_dev
+  .detect_dev = grub_ohci_detect_dev,
+  /* estimated max. count of TDs for one bulk transfer */
+  .max_bulk_tds = GRUB_OHCI_TDS * 3 / 4
 };
 
 static struct grub_preboot *fini_hnd;
diff -purB ./grub/grub-core/bus/usb/uhci.c ./grub_patched/grub-core/bus/usb/uhci.c
--- ./grub/grub-core/bus/usb/uhci.c	2013-01-27 22:12:17.000000000 +0100
+++ ./grub_patched/grub-core/bus/usb/uhci.c	2013-02-11 22:28:37.000000000 +0100
@@ -823,7 +823,9 @@ static struct grub_usb_controller_dev us
   .cancel_transfer = grub_uhci_cancel_transfer,
   .hubports = grub_uhci_hubports,
   .portstatus = grub_uhci_portstatus,
-  .detect_dev = grub_uhci_detect_dev
+  .detect_dev = grub_uhci_detect_dev,
+  /* estimated max. count of TDs for one bulk transfer */
+  .max_bulk_tds = N_TD * 3 / 4
 };
 
 GRUB_MOD_INIT(uhci)
diff -purB ./grub/grub-core/bus/usb/usbtrans.c ./grub_patched/grub-core/bus/usb/usbtrans.c
--- ./grub/grub-core/bus/usb/usbtrans.c	2013-01-27 22:12:17.000000000 +0100
+++ ./grub_patched/grub-core/bus/usb/usbtrans.c	2013-02-11 22:28:04.000000000 +0100
@@ -354,13 +354,36 @@ grub_usb_bulk_read (grub_usb_device_t de
   grub_size_t actual, transferred;
   grub_usb_err_t err;
   grub_size_t current_size, position;
+  grub_size_t max_bulk_transfer_len = MAX_USB_TRANSFER_LEN;
+  grub_size_t max;
+
+  if (dev->controller.dev->max_bulk_tds)
+    {
+      /* Use the maximum packet size given in the endpoint descriptor.  */
+      /* This must be the same "calculation" of "max" as inside function */
+      /* grub_usb_bulk_setup_readwrite (should we create some function */
+      /* for it to prevent problems?) */
+      if (dev->initialized)
+        {
+          struct grub_usb_desc_endp *endpdesc;
+          endpdesc = grub_usb_get_endpdescriptor (dev, endpoint);
+          if (endpdesc)
+	    max = endpdesc->maxpacket;
+          else
+	    max = 64;
+        }
+      else
+        max = 64;
+      /* Calculate max. possible length of bulk transfer */
+      max_bulk_transfer_len = dev->controller.dev->max_bulk_tds * max;
+    }
 
   for (position = 0, transferred = 0;
-       position < size; position += MAX_USB_TRANSFER_LEN)
+       position < size; position += max_bulk_transfer_len)
     {
       current_size = size - position;
-      if (current_size >= MAX_USB_TRANSFER_LEN)
-	current_size = MAX_USB_TRANSFER_LEN;
+      if (current_size >= max_bulk_transfer_len)
+	current_size = max_bulk_transfer_len;
       err = grub_usb_bulk_readwrite (dev, endpoint, current_size,
               &data[position], GRUB_USB_TRANSFER_TYPE_IN, 1000, &actual);
       transferred += actual;
diff -purB ./grub/include/grub/usb.h ./grub_patched/include/grub/usb.h
--- ./grub/include/grub/usb.h	2013-01-27 22:12:17.000000000 +0100
+++ ./grub_patched/include/grub/usb.h	2013-02-11 22:15:51.000000000 +0100
@@ -124,6 +124,13 @@ struct grub_usb_controller_dev
 
   /* Per controller flag - port reset pending, don't do another reset */
   grub_uint64_t pending_reset;
+
+  /* Max. number of transfer descriptors used per one bulk transfer */
+  /* The reason is to prevent "exhausting" of TD by large bulk */
+  /* transfer - number of TD is limited in USB host driver */
+  /* Value is calculated/estimated in driver - some TDs should be */
+  /* reserved for posible concurrent control or "interrupt" transfers */
+  grub_size_t max_bulk_tds;
   
   /* The next host controller.  */
   struct grub_usb_controller_dev *next;