diff --git a/include/haproxy/mux_quic-t.h b/include/haproxy/mux_quic-t.h
index 43a7cccb8..4ce088e61 100644
--- a/include/haproxy/mux_quic-t.h
+++ b/include/haproxy/mux_quic-t.h
@@ -30,7 +30,6 @@ enum qcs_type {
 #define QC_CF_CC_EMIT   0x00000001 /* A CONNECTION_CLOSE is set by the MUX */
 #define QC_CF_BLK_MFCTL 0x00000002 /* sending blocked due to connection flow-control */
 #define QC_CF_CONN_FULL 0x00000004 /* no stream buffers available on connection */
-#define QC_CF_APP_FINAL 0x00000008 /* The application layer was finalized */
 
 struct qcc {
 	struct connection *conn;
diff --git a/src/h3.c b/src/h3.c
index f7bd8a12c..9a1d97d40 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -1636,6 +1636,10 @@ static void h3_detach(struct qcs *qcs)
 	TRACE_LEAVE(H3_EV_H3S_END, qcs->qcc->conn, qcs);
 }
 
+/* Initialize H3 control stream and prepare SETTINGS emission.
+ *
+ * Returns 0 on success else non-zero.
+ */
 static int h3_finalize(void *ctx)
 {
 	struct h3c *h3c = ctx;
@@ -1643,12 +1647,12 @@ static int h3_finalize(void *ctx)
 
 	qcs = qcc_init_stream_local(h3c->qcc, 0);
 	if (!qcs)
-		return 0;
+		return 1;
 
 	h3_control_send(qcs, h3c);
 	h3c->ctrl_strm = qcs;
 
-	return 1;
+	return 0;
 }
 
 /* Generate a GOAWAY frame for <h3c> connection on the control stream.
diff --git a/src/mux_quic.c b/src/mux_quic.c
index 31d5a3ab0..b7b843e35 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -883,6 +883,21 @@ int qcc_install_app_ops(struct qcc *qcc, const struct qcc_app_ops *app_ops)
 
 	TRACE_PROTO("application layer initialized", QMUX_EV_QCC_NEW, qcc->conn);
 
+	/* RFC 9114 7.2.4.2. Initialization
+	 *
+	 * Endpoints MUST NOT require any data to be
+	 * received from the peer prior to sending the SETTINGS frame;
+	 * settings MUST be sent as soon as the transport is ready to
+	 * send data.
+	 */
+	if (qcc->app_ops->finalize) {
+		if (qcc->app_ops->finalize(qcc->ctx)) {
+			TRACE_ERROR("app ops finalize error", QMUX_EV_QCC_NEW, qcc->conn);
+			goto err;
+		}
+		tasklet_wakeup(qcc->wait_event.tasklet);
+	}
+
 	TRACE_LEAVE(QMUX_EV_QCC_NEW, qcc->conn);
 	return 0;
 
@@ -1741,15 +1756,6 @@ static int qc_send(struct qcc *qcc)
 	if (qcc->flags & QC_CF_BLK_MFCTL)
 		goto err;
 
-	if (!(qcc->flags & QC_CF_APP_FINAL) && !eb_is_empty(&qcc->streams_by_id) &&
-	    qcc->app_ops->finalize) {
-		/* Finalize the application layer before sending any stream.
-		 * For h3 this consists in preparing the control stream data (SETTINGS h3).
-		 */
-		qcc->app_ops->finalize(qcc->ctx);
-		qcc->flags |= QC_CF_APP_FINAL;
-	}
-
 	/* Send STREAM/STOP_SENDING/RESET_STREAM data for registered streams. */
 	list_for_each_entry_safe(qcs, qcs_tmp, &qcc->send_list, el_send) {
 		/* Stream must not be present in send_list if it has nothing to send. */