Index: jtagmkII.c
===================================================================
--- jtagmkII.c	(revision 1334)
+++ jtagmkII.c	(working copy)
@@ -1507,9 +1507,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_JTAGICEMKII;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -1559,9 +1559,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_JTAGICEMKII;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -1611,9 +1611,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_JTAGICEMKII;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -1664,9 +1664,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_AVRDRAGON;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -1717,9 +1717,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_AVRDRAGON;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -1770,9 +1770,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_AVRDRAGON;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -3347,9 +3347,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_JTAGICEMKII;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
Index: stk500v2.c
===================================================================
--- stk500v2.c	(revision 1334)
+++ stk500v2.c	(working copy)
@@ -1597,9 +1597,9 @@
     pinfo.usbinfo.pid = USB_DEVICE_AVRISPMKII;
     PDATA(pgm)->pgmtype = PGMTYPE_AVRISP_MKII;
     pgm->set_sck_period = stk500v2_set_sck_period_mk2;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -1655,7 +1655,7 @@
     pinfo.usbinfo.pid = USB_DEVICE_STK600;
     PDATA(pgm)->pgmtype = PGMTYPE_STK600;
     pgm->set_sck_period = stk600_set_sck_period;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
+    pgm->fd.usb.max_xfer = 0;
     pgm->fd.usb.rep = USBDEV_BULK_EP_READ_STK600;
     pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_STK600;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
@@ -3361,9 +3361,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_JTAGICEMKII;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -3472,9 +3472,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_AVRDRAGON;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
@@ -3550,9 +3550,9 @@
     pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
     pinfo.usbinfo.flags = 0;
     pinfo.usbinfo.pid = USB_DEVICE_AVRDRAGON;
-    pgm->fd.usb.max_xfer = USBDEV_MAX_XFER_MKII;
-    pgm->fd.usb.rep = USBDEV_BULK_EP_READ_MKII;
-    pgm->fd.usb.wep = USBDEV_BULK_EP_WRITE_MKII;
+    pgm->fd.usb.max_xfer = 0;
+    pgm->fd.usb.rep = -1;
+    pgm->fd.usb.wep = -1;
     pgm->fd.usb.eep = 0;           /* no seperate EP for events */
 #else
     avrdude_message(MSG_INFO, "avrdude was compiled without usb support.\n");
Index: usb_libusb.c
===================================================================
--- usb_libusb.c	(revision 1334)
+++ usb_libusb.c	(working copy)
@@ -104,9 +104,6 @@
 	}
     }
 
-  if (fd->usb.max_xfer == 0)
-    fd->usb.max_xfer = USBDEV_MAX_XFER_MKII;
-
   usb_init();
 
   usb_find_busses();
@@ -239,43 +236,62 @@
 		    }
 
 		  fd->usb.handle = udev;
-		  if (fd->usb.rep == 0)
+		  if (fd->usb.rep < 0)
 		    {
 		      /* Try finding out what our read endpoint is. */
 		      for (i = 0; i < dev->config[0].interface[iface].altsetting[0].bNumEndpoints; i++)
 			{
-			  int possible_ep = dev->config[0].interface[iface].altsetting[0].
-			  endpoint[i].bEndpointAddress;
+			  int possible_ep = dev->config[0].interface[iface].altsetting[0].endpoint[i].bEndpointAddress;
+			  int possible_ep_size = dev->config[0].interface[iface].altsetting[0].endpoint[i].wMaxPacketSize;
 
 			  if ((possible_ep & USB_ENDPOINT_DIR_MASK) != 0)
 			    {
-                              avrdude_message(MSG_NOTICE2, "%s: usbdev_open(): using read endpoint 0x%02x\n",
+				  avrdude_message(MSG_NOTICE2, "%s: usbdev_open(): using read endpoint 0x%02x\n",
                                                   progname, possible_ep);
 			      fd->usb.rep = possible_ep;
+				  //Take smaller endpoint size as max
+				  if ((fd->usb.max_xfer == 0) || (possible_ep_size < fd->usb.max_xfer))
+				  {
+				    fd->usb.max_xfer = possible_ep_size;
+				  }
 			      break;
 			    }
 			}
-		      if (fd->usb.rep == 0)
+		      if (fd->usb.rep < 0)
 			{
-			  avrdude_message(MSG_INFO, "%s: usbdev_open(): cannot find a read endpoint, using 0x%02x\n",
-                                          progname, USBDEV_BULK_EP_READ_MKII);
-			  fd->usb.rep = USBDEV_BULK_EP_READ_MKII;
+			  avrdude_message(MSG_INFO, "%s: usbdev_open(): ERROR: cannot find a read endpoint",
+                                          progname);
 			}
 		    }
-		  for (i = 0; i < dev->config[0].interface[iface].altsetting[0].bNumEndpoints; i++)
+
+		  if (fd->usb.wep < 0)
 		    {
-		      if ((dev->config[0].interface[iface].altsetting[0].endpoint[i].bEndpointAddress == fd->usb.rep ||
-			   dev->config[0].interface[iface].altsetting[0].endpoint[i].bEndpointAddress == fd->usb.wep) &&
-			  dev->config[0].interface[iface].altsetting[0].endpoint[i].wMaxPacketSize < fd->usb.max_xfer)
+		      /* Try finding out what our write endpoint is. */
+		      for (i = 0; i < dev->config[0].interface[iface].altsetting[0].bNumEndpoints; i++)
 			{
-                          avrdude_message(MSG_NOTICE, "%s: max packet size expected %d, but found %d due to EP 0x%02x's wMaxPacketSize\n",
-                                            progname,
-                                            fd->usb.max_xfer,
-                                            dev->config[0].interface[iface].altsetting[0].endpoint[i].wMaxPacketSize,
-                                            dev->config[0].interface[iface].altsetting[0].endpoint[i].bEndpointAddress);
-			  fd->usb.max_xfer = dev->config[0].interface[iface].altsetting[0].endpoint[i].wMaxPacketSize;
+			  int possible_ep = dev->config[0].interface[iface].altsetting[0].endpoint[i].bEndpointAddress;
+			  int possible_ep_size = dev->config[0].interface[iface].altsetting[0].endpoint[i].wMaxPacketSize;
+
+			  if ((possible_ep & USB_ENDPOINT_DIR_MASK) == 0)
+			    {
+				  avrdude_message(MSG_NOTICE2, "%s: usbdev_open(): using write endpoint 0x%02x\n",
+                                                  progname, possible_ep);
+			      fd->usb.wep = possible_ep;
+				  //Take smaller endpoint size as max
+				  if ((fd->usb.max_xfer == 0) || (possible_ep_size < fd->usb.max_xfer))
+				  {
+				    fd->usb.max_xfer = possible_ep_size;
+				  }
+			      break;
+			    }
 			}
+		      if (fd->usb.wep < 0)
+			{
+			  avrdude_message(MSG_INFO, "%s: usbdev_open(): ERROR: cannot find a write endpoint",
+                                          progname);
+			}
 		    }
+		 
 		  if (pinfo.usbinfo.flags & PINFO_FL_USEHID)
 		    {
 		      if (usb_control_msg(udev, 0x21, 0x0a /* SET_IDLE */, 0, 0, NULL, 0, 100) < 0)
Index: usbdevs.h
===================================================================
--- usbdevs.h	(revision 1334)
+++ usbdevs.h	(working copy)
@@ -55,12 +55,6 @@
 #define USBTINY_PRODUCT_DEFAULT 0x0C9F
 
 
-
-/* JTAGICEmkII, AVRISPmkII */
-#define USBDEV_BULK_EP_WRITE_MKII 0x02
-#define USBDEV_BULK_EP_READ_MKII  0x82
-#define USBDEV_MAX_XFER_MKII 64
-
 /* STK600 */
 #define USBDEV_BULK_EP_WRITE_STK600 0x02
 #define USBDEV_BULK_EP_READ_STK600 0x83