diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index c17d680..34c576d 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -2307,7 +2307,7 @@
 		return (port1->iobase == port2->iobase) &&
 		       (port1->hub6   == port2->hub6);
 	case UPIO_MEM:
-		return (port1->membase == port2->membase);
+		return (port1->mapbase == port2->mapbase);
 	}
 	return 0;
 }