diff --git a/mt76_connac_mac.c b/mt76_connac_mac.c
index fd60123f..c8d0c84e 100644
--- a/mt76_connac_mac.c
+++ b/mt76_connac_mac.c
@@ -930,7 +930,7 @@ int mt76_connac2_reverse_frag0_hdr_trans(struct ieee80211_vif *vif,
 		ether_addr_copy(hdr.addr4, eth_hdr->h_source);
 		break;
 	default:
-		break;
+		return -EINVAL;
 	}
 
 	skb_pull(skb, hdr_offset + sizeof(struct ethhdr) - 2);