diff --git a/mt7915/main.c b/mt7915/main.c
index 6ce228bd..f93dbc61 100644
--- a/mt7915/main.c
+++ b/mt7915/main.c
@@ -245,7 +245,9 @@ static int mt7915_add_interface(struct ieee80211_hw *hw,
 	dev->mt76.vif_mask |= BIT_ULL(mvif->mt76.idx);
 	phy->omac_mask |= BIT_ULL(mvif->mt76.omac_idx);
 
-	idx = MT7915_WTBL_RESERVED - mvif->mt76.idx;
+	idx = mt76_wcid_alloc(dev->mt76.wcid_mask, mt7915_wtbl_size(dev));
+	if (idx < 0)
+		return -ENOSPC;
 
 	INIT_LIST_HEAD(&mvif->sta.rc_list);
 	INIT_LIST_HEAD(&mvif->sta.wcid.poll_list);