diff --git a/include/common/htx.h b/include/common/htx.h
index ec9909851..25c28c8c4 100644
--- a/include/common/htx.h
+++ b/include/common/htx.h
@@ -161,7 +161,7 @@ struct htx {
 	uint64_t extra;  /* known bytes amount remaining to receive */
 	uint32_t flags;  /* HTX_FL_* */
 
-	int32_t sl_pos; /* position of the start-line of the HTTP message. -1 if unset */
+	int32_t  first;  /* position of the first block to (re)start the analyse. -1 if unset. */
 
 	struct htx_blk blocks[0]; /* Blocks representing the HTTP message itself */
 };
@@ -413,8 +413,8 @@ static inline enum htx_blk_type htx_get_tail_type(const struct htx *htx)
 	return (blk ? htx_get_blk_type(blk) : HTX_BLK_UNUSED);
 }
 
-/* Returns the position of the first block in the HTX message <htx>. It is the
- * sl_pos if set, otherwise it is the head.
+/* Returns the position of the first block in the HTX message <htx>. If unset,
+ * or if <htx> is empty, -1 is returned.
  *
  * An signed 32-bits integer is returned to handle -1 case. Blocks position are
  * store on unsigned 32-bits integer, but it is impossible to have so much
@@ -422,13 +422,13 @@ static inline enum htx_blk_type htx_get_tail_type(const struct htx *htx)
  */
 static inline int32_t htx_get_first(const struct htx *htx)
 {
-	if (htx->sl_pos != -1)
-		return htx->sl_pos;
-	return htx->head;
+	if (!htx->used)
+		return -1;
+	return htx->first;
 }
 
-/* Returns the first HTX block in the HTX message <htx>. If <blk> is the head,
- * NULL returned.
+/* Returns the first HTX block in the HTX message <htx>. If unset or if <htx> is
+ * empty, NULL returned.
  */
 static inline struct htx_blk *htx_get_first_blk(const struct htx *htx)
 {
@@ -717,7 +717,7 @@ static inline void htx_reset(struct htx *htx)
 	htx->data = htx->used = htx->tail = htx->head  = htx->front = 0;
 	htx->extra = 0;
 	htx->flags = HTX_FL_NONE;
-	htx->sl_pos = -1;
+	htx->first = -1;
 }
 
 /* returns the available room for raw data in buffer <buf> once HTX overhead is
@@ -832,8 +832,8 @@ static inline void htx_dump(struct htx *htx)
 	fprintf(stderr, "htx:%p [ size=%u - data=%u - used=%u - wrap=%s - extra=%llu]\n",
 		htx, htx->size, htx->data, htx->used, (htx->tail >= htx->head) ? "NO" : "YES",
 		(unsigned long long)htx->extra);
-	fprintf(stderr, "\tsl_pos=%d - head=%u, tail=%u - front=%u\n",
-		htx->sl_pos, htx->head, htx->tail, htx->front);
+	fprintf(stderr, "\tfirst=%d - head=%u, tail=%u - front=%u\n",
+		htx->first, htx->head, htx->tail, htx->front);
 
 	for (pos = htx_get_head(htx); pos != -1; pos = htx_get_next(htx, pos)) {
 		struct htx_sl     *sl;
diff --git a/include/proto/channel.h b/include/proto/channel.h
index 077b3ae1f..3ebaf7fce 100644
--- a/include/proto/channel.h
+++ b/include/proto/channel.h
@@ -923,7 +923,7 @@ static inline void channel_htx_fwd_headers(struct channel *chn, struct htx *htx)
 		struct htx_blk *blk = htx_get_blk(htx, pos);
 		data += htx_get_blksz(blk);
 		if (htx_get_blk_type(blk) == HTX_BLK_EOH) {
-			htx->sl_pos = htx_get_next(htx, pos);
+			htx->first = htx_get_next(htx, pos);
 			break;
 		}
 	}
diff --git a/src/cache.c b/src/cache.c
index 1fec57e24..4371910fc 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -913,10 +913,6 @@ static size_t htx_cache_dump_headers(struct appctx *appctx, struct htx *htx)
 		if (!blk)
 			return 0;
 
-		/* Set the start-line offset */
-		if (type == HTX_BLK_RES_SL)
-			htx->sl_pos = htx_get_blk_pos(htx, blk);
-
 		/* Copy info and data */
 		blk->info = info;
 		memcpy(htx_get_blk_ptr(htx, blk), b_peek(tmp, offset+4), sz);
diff --git a/src/hlua.c b/src/hlua.c
index bb8c93da6..3c9c70a78 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -3944,11 +3944,16 @@ static int hlua_applet_http_new(lua_State *L, struct appctx *ctx)
 	if (IS_HTX_STRM(s)) {
 		/* HTX version */
 		struct htx *htx = htxbuf(&s->req.buf);
-		struct htx_sl *sl = http_get_stline(htx);
+		struct htx_blk *blk;
+		struct htx_sl *sl;
 		struct ist path;
 		unsigned long long len = 0;
 		int32_t pos;
 
+		blk = htx_get_first_blk(htx);
+		BUG_ON(htx_get_blk_type(blk) != HTX_BLK_REQ_SL);
+		sl = htx_get_blk_ptr(htx, blk);
+
 		/* Stores the request method. */
 		lua_pushstring(L, "method");
 		lua_pushlstring(L, HTX_SL_REQ_MPTR(sl), HTX_SL_REQ_MLEN(sl));
@@ -4366,7 +4371,7 @@ __LJMP static int hlua_applet_htx_recv_yield(lua_State *L, int status, lua_KCont
 	htx = htx_from_buf(&req->buf);
 	len = MAY_LJMP(luaL_checkinteger(L, 2));
 	count = co_data(req);
-	blk = htx_get_first_blk(htx);
+	blk = htx_get_head_blk(htx);
 	while (count && len && blk) {
 		enum htx_blk_type type = htx_get_blk_type(blk);
 		uint32_t sz = htx_get_blksz(blk);
diff --git a/src/http_fetch.c b/src/http_fetch.c
index 05074d6eb..a184f2f3b 100644
--- a/src/http_fetch.c
+++ b/src/http_fetch.c
@@ -203,7 +203,7 @@ struct htx *smp_prefetch_htx(struct sample *smp, struct channel *chn, int vol)
 
 		if (msg->msg_state < HTTP_MSG_BODY) {
 			/* Analyse not yet started */
-			if (htx_is_empty(htx) || htx->sl_pos == -1) {
+			if (htx_is_empty(htx) || htx->first == -1) {
 				/* Parsing is done by the mux, just wait */
 				smp->flags |= SMP_F_MAY_CHANGE;
 				return NULL;
diff --git a/src/http_htx.c b/src/http_htx.c
index 15865d502..b9501bed7 100644
--- a/src/http_htx.c
+++ b/src/http_htx.c
@@ -11,6 +11,7 @@
  */
 
 #include <common/config.h>
+#include <common/debug.h>
 #include <common/cfgparse.h>
 #include <common/h1.h>
 #include <common/http.h>
@@ -21,19 +22,18 @@
 struct buffer htx_err_chunks[HTTP_ERR_SIZE];
 
 /* Returns the next unporocessed start line in the HTX message. It returns NULL
- * is the start-line is undefined (sl_pos == 1). Otherwise, it returns the
+ * if the start-line is undefined (first == -1). Otherwise, it returns the
  * pointer on the htx_sl structure.
  */
 struct htx_sl *http_get_stline(struct htx *htx)
 {
 	struct htx_blk *blk;
 
-	if (htx->sl_pos == -1)
-		return NULL;
-
-	blk = htx_get_blk(htx, htx->sl_pos);
+	BUG_ON(htx->first == -1);
+	blk = htx_get_first_blk(htx);
 	if (!blk)
 		return NULL;
+	BUG_ON(htx_get_blk_type(blk) != HTX_BLK_REQ_SL && htx_get_blk_type(blk) != HTX_BLK_RES_SL);
 	return htx_get_blk_ptr(htx, blk);
 }
 
@@ -143,7 +143,7 @@ int http_add_header(struct htx *htx, const struct ist n, const struct ist v)
 
 	/* <blk> is the head, swap it iteratively with its predecessor to place
 	 * it just before the end-of-header block. So blocks remains ordered. */
-	for (prev = htx_get_prev(htx, htx->tail); prev != htx->sl_pos; prev = htx_get_prev(htx, prev)) {
+	for (prev = htx_get_prev(htx, htx->tail); prev != htx->first; prev = htx_get_prev(htx, prev)) {
 		struct htx_blk   *pblk = htx_get_blk(htx, prev);
 		enum htx_blk_type type = htx_get_blk_type(pblk);
 
@@ -169,18 +169,14 @@ int http_add_header(struct htx *htx, const struct ist n, const struct ist v)
 }
 
 /* Replaces parts of the start-line of the HTX message <htx>. It returns 1 on
- * success, otherwise it returns 0. The right block is search in the HTX
- * message.
+ * success, otherwise it returns 0.
  */
 int http_replace_stline(struct htx *htx, const struct ist p1, const struct ist p2, const struct ist p3)
 {
 	struct htx_blk *blk;
 
-	if (htx->sl_pos == -1)
-		return 0;
-
-	blk = htx_get_blk(htx, htx->sl_pos);
-	if (!htx_replace_stline(htx, blk, p1, p2, p3))
+	blk = htx_get_first_blk(htx);
+	if (!blk || !htx_replace_stline(htx, blk, p1, p2, p3))
 		return 0;
 	return 1;
 }
diff --git a/src/htx.c b/src/htx.c
index a7623b6d9..dbf8dea37 100644
--- a/src/htx.c
+++ b/src/htx.c
@@ -28,7 +28,7 @@ struct htx_blk *htx_defrag(struct htx *htx, struct htx_blk *blk)
 	struct htx_blk *newblk, *oldblk;
 	uint32_t new, old, blkpos;
 	uint32_t addr, blksz;
-	int32_t sl_pos = -1;
+	int32_t first = -1;
 
 	if (!htx->used)
 		return NULL;
@@ -51,8 +51,8 @@ struct htx_blk *htx_defrag(struct htx *htx, struct htx_blk *blk)
 		blksz = htx_get_blksz(oldblk);
 
 		/* update the start-line position */
-		if (htx->sl_pos == old)
-			sl_pos = new;
+		if (htx->first == old)
+			first = new;
 
 		/* if <blk> is defined, set its new position */
 		if (blk != NULL && blk == oldblk)
@@ -65,7 +65,7 @@ struct htx_blk *htx_defrag(struct htx *htx, struct htx_blk *blk)
 	}
 
 	htx->used = new;
-	htx->sl_pos = sl_pos;
+	htx->first = first;
 	htx->head = 0;
 	htx->front = htx->tail = new - 1;
 	memcpy((void *)htx->blocks, (void *)tmp->blocks, htx->size);
@@ -94,7 +94,7 @@ static struct htx_blk *htx_reserve_nxblk(struct htx *htx, uint32_t blksz)
 
 	if (!htx->used) {
 		/* Empty message */
-		htx->front = htx->head = htx->tail = 0;
+		htx->front = htx->head = htx->tail = htx->first = 0;
 		htx->used = 1;
 		blk = htx_get_blk(htx, htx->tail);
 		blk->addr = 0;
@@ -188,6 +188,9 @@ static struct htx_blk *htx_reserve_nxblk(struct htx *htx, uint32_t blksz)
 	htx->tail  = tail;
 	htx->used  = used;
 	htx->data += blksz;
+	/* Set first position if not already set */
+	if (htx->first == -1)
+		htx->first = tail;
 	return blk;
 }
 
@@ -220,15 +223,11 @@ struct htx_blk *htx_remove_blk(struct htx *htx, struct htx_blk *blk)
 		/* Mark the block as unused, decrement allocated size */
 		htx->data -= htx_get_blksz(blk);
 		blk->info = ((uint32_t)HTX_BLK_UNUSED << 28);
-		if (htx->sl_pos == pos)
-			htx->sl_pos = -1;
 	}
 
 	/* This is the last block in use */
-	if (htx->used == 1/* || !htx->data */) {
-		htx->front = htx->head = htx->tail = 0;
-		htx->used = 0;
-		htx->data = 0;
+	if (htx->used == 1) {
+		htx_reset(htx);
 		return NULL;
 	}
 
@@ -271,13 +270,9 @@ struct htx_blk *htx_remove_blk(struct htx *htx, struct htx_blk *blk)
 	}
 
 	blk = htx_get_blk(htx, next);
-	if (htx->sl_pos == -1) {
-		/* Try to update the start-line payload addr, if possible */
-		type = htx_get_blk_type(blk);
-		if (type == HTX_BLK_REQ_SL || type == HTX_BLK_RES_SL)
-			htx->sl_pos = htx_get_blk_pos(htx, blk);
-	}
   end:
+	if (pos == htx->first)
+		htx->first = (blk ? htx_get_blk_pos(htx, blk) : -1);
 	if (pos == htx->front)
 		htx->front = htx_find_front(htx);
 	return blk;
@@ -542,9 +537,6 @@ struct htx_ret htx_xfer_blks(struct htx *dst, struct htx *src, uint32_t count,
 			htx_cut_data_blk(src, blk, sz);
 			break;
 		}
-
-		if (dst->sl_pos == -1 && src->sl_pos == htx_get_blk_pos(src, blk))
-			dst->sl_pos = htx_get_blk_pos(dst, dstblk);
 	  next:
 		blk = htx_remove_blk(src, blk);
 		if (type == mark)
@@ -682,8 +674,6 @@ struct htx_sl *htx_add_stline(struct htx *htx, enum htx_blk_type type, unsigned
 	blk->info += size;
 
 	sl = htx_get_blk_ptr(htx, blk);
-	if (htx->sl_pos == -1)
-		htx->sl_pos = htx_get_blk_pos(htx, blk);
 	sl->hdrs_bytes = -1;
 	sl->flags = flags;
 
diff --git a/src/proto_htx.c b/src/proto_htx.c
index dc0762d73..7cc26ba31 100644
--- a/src/proto_htx.c
+++ b/src/proto_htx.c
@@ -132,7 +132,7 @@ int htx_wait_for_request(struct stream *s, struct channel *req, int an_bit)
 	 * a timeout or connection reset is not counted as an error. However
 	 * a bad request is.
 	 */
-	if (unlikely(htx_is_empty(htx) || htx->sl_pos == -1)) {
+	if (unlikely(htx_is_empty(htx) || htx->first == -1)) {
 		if (htx->flags & HTX_FL_UPGRADE)
 			goto failed_keep_alive;
 
@@ -279,6 +279,7 @@ int htx_wait_for_request(struct stream *s, struct channel *req, int an_bit)
 	txn->flags &= ~TX_WAIT_NEXT_RQ;
 	req->analyse_exp = TICK_ETERNITY;
 
+	BUG_ON(htx_get_first_type(htx) != HTX_BLK_REQ_SL);
 	sl = http_get_stline(htx);
 
 	/* 0: we might have to print this header in debug mode */
@@ -1470,7 +1471,7 @@ int htx_wait_for_response(struct stream *s, struct channel *rep, int an_bit)
 	 * errors somewhere else.
 	 */
   next_one:
-	if (unlikely(htx_is_empty(htx) || htx->sl_pos == -1)) {
+	if (unlikely(htx_is_empty(htx) || htx->first == -1)) {
 		/* 1: have we encountered a read error ? */
 		if (rep->flags & CF_READ_ERROR) {
 			struct connection *conn = NULL;
@@ -1625,6 +1626,7 @@ int htx_wait_for_response(struct stream *s, struct channel *rep, int an_bit)
 	 */
 
 	msg->msg_state = HTTP_MSG_BODY;
+	BUG_ON(htx_get_first_type(htx) != HTX_BLK_RES_SL);
 	sl = http_get_stline(htx);
 
 	/* 0: we might have to print this header in debug mode */