diff --git a/aucat/dev.c b/aucat/dev.c
index e52aa1f..f15f305 100644
--- a/aucat/dev.c
+++ b/aucat/dev.c
@@ -1350,7 +1350,7 @@ dev_mkslot(struct dev *d, char *who)
 		if (slot->ops == NULL)
 			continue;
 		if (strcmp(slot->name, name) == 0)
-			umap |= (1 << i);
+			umap |= (1 << slot->unit);
 	} 
 	for (unit = 0; ; unit++) {
 		if (unit == CTL_NSLOT) {