diff -up cups-1.4rc1/backend/ieee1284.c.device-id cups-1.4rc1/backend/ieee1284.c
--- cups-1.4rc1/backend/ieee1284.c.device-id	2009-07-18 18:25:38.355769382 +0100
+++ cups-1.4rc1/backend/ieee1284.c	2009-07-18 18:25:43.844894365 +0100
@@ -196,12 +196,19 @@ backendGetDeviceID(
       * and then limit the length to the size of our buffer...
       */
 
-      if (length > (device_id_size - 2))
+      if (length > device_id_size)
 	length = (((unsigned)device_id[1] & 255) << 8) +
 		 ((unsigned)device_id[0] & 255);
 
-      if (length > (device_id_size - 2))
-	length = device_id_size - 2;
+      if (length > device_id_size)
+	length = device_id_size;
+
+     /*
+      * The length field counts the number of bytes in the string
+      * including the length field itself (2 bytes).
+      */
+
+      length -= 2;
 
      /*
       * Copy the device ID text to the beginning of the buffer and
diff -up cups-1.4rc1/backend/usb-libusb.c.device-id cups-1.4rc1/backend/usb-libusb.c
--- cups-1.4rc1/backend/usb-libusb.c.device-id	2009-01-14 19:46:43.000000000 +0000
+++ cups-1.4rc1/backend/usb-libusb.c	2009-07-18 18:25:43.845895048 +0100
@@ -418,12 +418,14 @@ get_device_id(usb_printer_t *printer,	/*
   * and then limit the length to the size of our buffer...
   */
 
-  if (length > (bufsize - 2))
+  if (length > bufsize)
     length = (((unsigned)buffer[1] & 255) << 8) +
 	     ((unsigned)buffer[0] & 255);
 
-  if (length > (bufsize - 2))
-    length = bufsize - 2;
+  if (length > bufsize)
+    length = bufsize;
+
+  length -= 2;
 
  /*
   * Copy the device ID text to the beginning of the buffer and