diff --git a/sys/src/9/port/devaoe.c b/sys/src/9/port/devaoe.c
index ce8f51ec7..ed091df0a 100644
--- a/sys/src/9/port/devaoe.c
+++ b/sys/src/9/port/devaoe.c
@@ -949,7 +949,7 @@ aoegen(Chan *c, char *, Dirtab *, int, int s, Dir *dp)
 		return unitgen(c, TYPE(c->qid), dp);
 	case Qdevlinkdir:
 		i = UNIT(c->qid);
-		if(i > Maxunits || i > units.ref)
+		if(i >= Maxunits || i >= units.ref)
 			return -1;
 		d = unit2dev(i);
 		if(s == DEVDOTDOT){
@@ -1728,7 +1728,7 @@ newunit(void)
 {
 	int x;
 
-	x = incref(&units);
+	x = incref(&units)-1;
 	if(x >= Maxunits){
 		decref(&units);
 		x = -1;