diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/main.c b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
index 54e79bd25995..e218856b0c45 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/main.c
@@ -1515,20 +1515,26 @@ static void mt7996_tx(struct ieee80211_hw *hw,
 	struct ieee80211_vif *vif = info->control.vif;
 	struct mt7996_vif *mvif = vif ? (void *)vif->drv_priv : NULL;
 	struct mt76_wcid *wcid = &dev->mt76.global_wcid;
+	u8 deflink_id = IEEE80211_LINK_UNSPECIFIED;
 	u8 link_id = u32_get_bits(info->control.flags,
 				  IEEE80211_TX_CTRL_MLO_LINK);
 
 	rcu_read_lock();
 
+	if (msta)
+		deflink_id = msta->deflink_id;
+	else if (mvif)
+		deflink_id = mvif->mt76.deflink_id;
+
+	/* the primary link is unset until the first link has been added */
+	if (deflink_id >= IEEE80211_MLD_MAX_NUM_LINKS)
+		deflink_id = 0;
+
 	/* Use primary link_id if the value from mac80211 is set to
 	 * IEEE80211_LINK_UNSPECIFIED.
 	 */
-	if (link_id == IEEE80211_LINK_UNSPECIFIED) {
-		if (msta)
-			link_id = msta->deflink_id;
-		else if (mvif)
-			link_id = mvif->mt76.deflink_id;
-	}
+	if (link_id == IEEE80211_LINK_UNSPECIFIED)
+		link_id = deflink_id;
 
 	if (vif && ieee80211_vif_is_mld(vif)) {
 		struct ieee80211_bss_conf *link_conf;
@@ -1538,7 +1544,7 @@ static void mt7996_tx(struct ieee80211_hw *hw,
 
 			link_sta = rcu_dereference(sta->link[link_id]);
 			if (!link_sta)
-				link_sta = rcu_dereference(sta->link[msta->deflink_id]);
+				link_sta = rcu_dereference(sta->link[deflink_id]);
 
 			if (link_sta) {
 				memcpy(hdr->addr1, link_sta->addr, ETH_ALEN);