diff --git a/src/device/serial.c b/src/device/serial.c
index 1587fbe03..3a5b237c2 100644
--- a/src/device/serial.c
+++ b/src/device/serial.c
@@ -112,7 +112,7 @@ serial_do_irq(serial_t *dev, int set)
     if (dev->irq != 0xff) {
         if (set || (dev->irq_state != !!set))
             picint_common(1 << dev->irq, !!(dev->type >= SERIAL_16450), set, &dev->irq_state);
-        if (dev->type >= SERIAL_16450)
+        if (dev->type < SERIAL_16450)
             dev->irq_state = !!set;
     }
 }