diff --git a/src/h3.c b/src/h3.c
index 68e302dfa..2898b9e41 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -1596,6 +1596,7 @@ static int h3_resp_headers_send(struct qcs *qcs, struct htx *htx)
 			hdr++;
 		}
 		else {
+			/* Unhandled HTX block type. */
 			ABORT_NOW();
 			goto err;
 		}
@@ -1615,9 +1616,8 @@ static int h3_resp_headers_send(struct qcs *qcs, struct htx *htx)
 		goto end;
 	}
 
-	/* At least 5 bytes to store frame type + length as a varint max size */
-	if (b_room(res) < 5)
-		ABORT_NOW();
+	/* Buffer allocated just now : must be enough for frame type + length as a max varint size */
+	BUG_ON(b_room(res) < 5);
 
 	b_reset(&outbuf);
 	outbuf = b_make(b_tail(res), b_contig_space(res), 0, 0);
@@ -1627,9 +1627,10 @@ static int h3_resp_headers_send(struct qcs *qcs, struct htx *htx)
 	TRACE_DATA("encoding HEADERS frame", H3_EV_TX_FRAME|H3_EV_TX_HDR,
 	           qcs->qcc->conn, qcs);
 	if (qpack_encode_field_section_line(&headers_buf))
-		ABORT_NOW();
+		goto err;
 	if (qpack_encode_int_status(&headers_buf, status)) {
-		TRACE_ERROR("invalid status code", H3_EV_TX_FRAME|H3_EV_TX_HDR, qcs->qcc->conn, qcs);
+		/* TODO handle invalid status code VS no buf space left */
+		TRACE_ERROR("error during status code encoding", H3_EV_TX_FRAME|H3_EV_TX_HDR, qcs->qcc->conn, qcs);
 		goto err;
 	}
 
@@ -1661,7 +1662,7 @@ static int h3_resp_headers_send(struct qcs *qcs, struct htx *htx)
 		}
 
 		if (qpack_encode_header(&headers_buf, list[hdr].n, list[hdr].v))
-			ABORT_NOW();
+			goto err;
 	}
 
 	/* Now that all headers are encoded, we are certain that res buffer is
@@ -1670,8 +1671,7 @@ static int h3_resp_headers_send(struct qcs *qcs, struct htx *htx)
 	frame_length_size = quic_int_getsize(b_data(&headers_buf));
 	res->head += 4 - frame_length_size;
 	b_putchr(res, 0x01); /* h3 HEADERS frame type */
-	if (!b_quic_enc_int(res, b_data(&headers_buf), 0))
-		ABORT_NOW();
+	b_quic_enc_int(res, b_data(&headers_buf), 0);
 	b_add(res, b_data(&headers_buf));
 
 	ret = 0;
@@ -1839,8 +1839,7 @@ static int h3_resp_trailers_send(struct qcs *qcs, struct htx *htx)
 		TRACE_DATA("encoding TRAILERS frame", H3_EV_TX_FRAME|H3_EV_TX_HDR,
 			   qcs->qcc->conn, qcs);
 		b_putchr(res, 0x01); /* h3 HEADERS frame type */
-		if (!b_quic_enc_int(res, b_data(&headers_buf), 8))
-			ABORT_NOW();
+		b_quic_enc_int(res, b_data(&headers_buf), 8);
 		b_add(res, b_data(&headers_buf));
 	}