diff --git a/sys/src/kern/amd64/usbuhci.c b/sys/src/kern/amd64/usbuhci.c
index 5ee9f56..1e51b13 100644
--- a/sys/src/kern/amd64/usbuhci.c
+++ b/sys/src/kern/amd64/usbuhci.c
@@ -2235,7 +2235,7 @@ init(Hci *hp)
 	/* guess other ports */
 	for(i = 2; i < 6; i++){
 		sts = INS(PORT(i));
-		if(sts != 0xFFFF && (sts & PSreserved1) == 1){
+		if(sts != 0xFFFF && (sts & PSreserved1) == PSreserved1){
 			dprint(" psc%d %#ux", i, sts);
 			hp->nports++;
 		}else