diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index e07a3a7f9..c18f174b4 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,8 @@
+2004-04-30  Corinna Vinschen  <corinna@vinschen.de>
+
+	* fhandler.cc (fhandler_base::open): Fix NT native path evaluation
+	to allow opening serial ports.
+
 2004-04-30  DJ Delorie  <dj@redhat.com>
 
 	* init.cc (threadfunc_fe): Hack to make thread stacks always 16
diff --git a/winsup/cygwin/fhandler.cc b/winsup/cygwin/fhandler.cc
index 445146aa9..2dc3eece0 100644
--- a/winsup/cygwin/fhandler.cc
+++ b/winsup/cygwin/fhandler.cc
@@ -554,21 +554,26 @@ fhandler_base::open (int flags, mode_t mode)
       set_errno (ENOENT);
       goto done;
     }
-  if (get_win32_name ()[0] == '\\')
-    {
-      if (get_win32_name ()[1] == '\\')
-        {
-	  str2buf2uni (upath, wpath, "\\??\\UNC");
-	  str2buf2uni_cat (upath, get_win32_name () + 1);
-	}
-      else
-	str2buf2uni (upath, wpath, get_win32_name ());
-    }
-  else
+
+  if (get_win32_name ()[0] != '\\')		/* X:\...  or NUL, etc. */
     {
       str2buf2uni (upath, wpath, "\\??\\");
       str2buf2uni_cat (upath, get_win32_name ());
     }
+  else if (get_win32_name ()[1] != '\\')	/* \Device\... */
+    str2buf2uni (upath, wpath, get_win32_name ());
+  else if (get_win32_name ()[2] != '.'
+  	   || get_win32_name ()[3] != '\\')	/* \\server\share\... */
+    {
+      str2buf2uni (upath, wpath, "\\??\\UNC\\");
+      str2buf2uni_cat (upath, get_win32_name () + 2);
+    }
+  else						/* \\.\device */
+    {
+      str2buf2uni (upath, wpath, "\\??\\");
+      str2buf2uni_cat (upath, get_win32_name () + 4);
+    }
+
   InitializeObjectAttributes (&attr, &upath, OBJ_CASE_INSENSITIVE | OBJ_INHERIT,
 			      sa.lpSecurityDescriptor, NULL);