diff --git a/mt76_connac_mcu.c b/mt76_connac_mcu.c
index e11db86f..a08d0f0d 100644
--- a/mt76_connac_mcu.c
+++ b/mt76_connac_mcu.c
@@ -937,8 +937,10 @@ void mt76_connac_mcu_wtbl_ba_tlv(struct mt76_dev *dev, struct sk_buff *skb,
 		ba->rst_ba_sb = 1;
 	}
 
-	if (is_mt7921(dev))
+	if (is_mt7921(dev)) {
+		ba->ba_winsize = enable ? cpu_to_le16(params->buf_size) : 0;
 		return;
+	}
 
 	if (enable && tx) {
 		u8 ba_range[] = { 4, 8, 12, 24, 36, 48, 54, 64 };