diff --git a/src/proto_alpha/lib_protocol/alpha_context.mli b/src/proto_alpha/lib_protocol/alpha_context.mli
index bd74853aa9244e1da9a20708b42ef1364ae4f758..867a6b1da8d500382072744819210e10ed1f1321 100644
--- a/src/proto_alpha/lib_protocol/alpha_context.mli
+++ b/src/proto_alpha/lib_protocol/alpha_context.mli
@@ -2881,6 +2881,11 @@ module Dal : sig
 
     val finalize_pending_slot_headers :
       context -> number_of_slots:int -> (context * Attestation.t) tzresult Lwt.t
+
+    val compute_attested_slot_headers :
+      is_slot_attested:(Header.t -> bool) ->
+      Header.t list ->
+      Header.t list * Attestation.t
   end
 
   module Operations : sig
diff --git a/src/proto_alpha/lib_protocol/dal_slot_repr.ml b/src/proto_alpha/lib_protocol/dal_slot_repr.ml
index a5d848ae8392e39f984f5368f22742f264be7de7..c1d216aee8850cbeace00167e4d7ac2354be263d 100644
--- a/src/proto_alpha/lib_protocol/dal_slot_repr.ml
+++ b/src/proto_alpha/lib_protocol/dal_slot_repr.ml
@@ -526,19 +526,20 @@ module History = struct
       let Header.{published_level; _} =
         Skip_list.content t |> Content.content_id
       in
-      if Raw_level_repr.equal published_level genesis_level then
-        (* If this is the first real cell of DAL, replace dummy genesis. *)
-        return (Skip_list.genesis next_cell_content, cache)
-      else
-        let* cache = History_cache.remember prev_cell_ptr t cache in
-        let* new_head =
+      let* new_head =
+        if Raw_level_repr.equal published_level genesis_level then
+          (* If this is the first real cell of DAL, replace dummy genesis. *)
+          return (Skip_list.genesis next_cell_content)
+        else
           Skip_list.next
             ~prev_cell:t
             ~prev_cell_ptr
             next_cell_content
             ~number_of_slots
-        in
-        return (new_head, cache)
+      in
+      let new_head_hash = hash new_head in
+      let* cache = History_cache.remember new_head_hash new_head cache in
+      return (new_head, cache)
 
     (* Given a list [attested_slot_headers] of well-ordered (wrt slots indices)
        (attested) slot headers, this function builds an extension [l] of
diff --git a/src/proto_alpha/lib_protocol/dal_slot_storage.ml b/src/proto_alpha/lib_protocol/dal_slot_storage.ml
index 699577121df3eec2ee83ea3d7c3538e6e9dbe9dd..30520c86d171e821150f0eaecbd9ad6acba804c5 100644
--- a/src/proto_alpha/lib_protocol/dal_slot_storage.ml
+++ b/src/proto_alpha/lib_protocol/dal_slot_storage.ml
@@ -32,18 +32,21 @@ let finalize_current_slot_headers ctxt =
   | [] -> Lwt.return ctxt
   | _ :: _ -> Storage.Dal.Slot.Headers.add ctxt current_level.level slot_headers
 
-let compute_attested_slot_headers ctxt seen_slot_headers =
+let compute_attested_slot_headers ~is_slot_attested seen_slot_headers =
   let open Dal_slot_repr in
   let fold_attested_slots (rev_attested_slot_headers, attestation) slot =
-    if Raw_context.Dal.is_slot_index_attested ctxt slot.Header.id.index then
+    if is_slot_attested slot then
       ( slot :: rev_attested_slot_headers,
         Dal_attestation_repr.commit attestation slot.Header.id.index )
     else (rev_attested_slot_headers, attestation)
   in
-  List.fold_left
-    fold_attested_slots
-    ([], Dal_attestation_repr.empty)
-    seen_slot_headers
+  let rev_attested_slot_headers, bitset =
+    List.fold_left
+      fold_attested_slots
+      ([], Dal_attestation_repr.empty)
+      seen_slot_headers
+  in
+  (List.rev rev_attested_slot_headers, bitset)
 
 let get_slot_headers_history ctxt =
   let open Lwt_result_syntax in
@@ -79,10 +82,14 @@ let finalize_pending_slot_headers ctxt ~number_of_slots =
         match seen_slots with
         | None -> return (ctxt, Dal_attestation_repr.empty, [])
         | Some seen_slots ->
-            let rev_attested_slot_headers, attestation =
-              compute_attested_slot_headers ctxt seen_slots
+            let attested_slot_headers, attestation =
+              let is_slot_attested slot =
+                Raw_context.Dal.is_slot_index_attested
+                  ctxt
+                  slot.Dal_slot_repr.Header.id.index
+              in
+              compute_attested_slot_headers ~is_slot_attested seen_slots
             in
-            let attested_slot_headers = List.rev rev_attested_slot_headers in
             return (ctxt, attestation, attested_slot_headers)
       in
       let* ctxt =
diff --git a/src/proto_alpha/lib_protocol/dal_slot_storage.mli b/src/proto_alpha/lib_protocol/dal_slot_storage.mli
index eafa34e3cc615acf520047f69ad8046b26073cf7..4dc2d270fca377d7bb566d726e436d56f39636cb 100644
--- a/src/proto_alpha/lib_protocol/dal_slot_storage.mli
+++ b/src/proto_alpha/lib_protocol/dal_slot_storage.mli
@@ -72,3 +72,11 @@ val finalize_pending_slot_headers :
    in [ctxt], or Slots_history.genesis if no value is stored yet. *)
 val get_slot_headers_history :
   Raw_context.t -> Dal_slot_repr.History.t tzresult Lwt.t
+
+(** [compute_attested_slot_headers ~is_slot_attested published_slot_headers]
+    filter the given [published_slot_headers] and return the list of attested
+    slot headers and the corresponding bitset. *)
+val compute_attested_slot_headers :
+  is_slot_attested:(Dal_slot_repr.Header.t -> bool) ->
+  Dal_slot_repr.Header.t list ->
+  Dal_slot_repr.Header.t list * Dal_attestation_repr.t