diff -r 9881884f8834 xen/drivers/char/ns16550.c
--- a/xen/drivers/char/ns16550.c	Fri Jun 04 15:10:01 2010 +0200
+++ b/xen/drivers/char/ns16550.c	Fri Jun 04 15:21:53 2010 +0200
@@ -408,7 +408,7 @@ static int __init check_existence(struct
      */
     ns_write_reg(uart, MCR, MCR_LOOP | 0x0A);
     status = ns_read_reg(uart, MSR) & 0xF0;
-    return (status == 0x90);
+    return (status == 0x90 || status == 0x30);
 }
 
 #define PARSE_ERR(_f, _a...)                 \