diff --git a/mt76_connac_mcu.c b/mt76_connac_mcu.c
index 261181dc..d32290d6 100644
--- a/mt76_connac_mcu.c
+++ b/mt76_connac_mcu.c
@@ -260,8 +260,10 @@ mt76_connac_mcu_add_nested_tlv(struct sk_buff *skb, int tag, int len,
 	ntlv = le16_to_cpu(ntlv_hdr->tlv_num);
 	ntlv_hdr->tlv_num = cpu_to_le16(ntlv + 1);
 
-	if (sta_hdr)
-		le16_add_cpu(&sta_hdr->len, len);
+	if (sta_hdr) {
+		len += le16_to_cpu(sta_hdr->len);
+		sta_hdr->len = cpu_to_le16(len);
+	}
 
 	return ptlv;
 }