diff --git a/src/proto_alpha/lib_protocol/init_storage.ml b/src/proto_alpha/lib_protocol/init_storage.ml
index e2e048a37e6200b355448582ff551cc25c609167..3af98031d1c17536ec0283f4bce17aa4a6d939f3 100644
--- a/src/proto_alpha/lib_protocol/init_storage.ml
+++ b/src/proto_alpha/lib_protocol/init_storage.ml
@@ -102,7 +102,27 @@ let patch_script (address, hash, patched_code) ctxt =
         address ;
       return ctxt
 
-let prepare_first_block _chain_id ctxt ~typecheck ~level ~timestamp =
+module Patch_ghostnet = struct
+  let ghostnet_id =
+    let id = Chain_id.of_b58check_exn "NetXnHfVqm9iesp" in
+    if Chain_id.equal id Constants_repr.mainnet_id then assert false else id
+
+  let patch chain_id ctxt level =
+    if Chain_id.equal chain_id ghostnet_id then
+      Raw_context.patch_constants ctxt (fun c ->
+          {c with vdf_difficulty = Int64.div c.vdf_difficulty 4L})
+      >>= fun ctxt ->
+      Voting_period_storage.get_current ctxt >>=? fun current ->
+      let level = Raw_level_repr.to_int32 level in
+      if Compare.Int32.equal current.start_position level then
+        (* do nothing; the migration happens at the end of a voting
+           period, so the period has already been reset *)
+        return ctxt
+      else Voting_period_storage.reset ctxt
+    else return ctxt
+end
+
+let prepare_first_block chain_id ctxt ~typecheck ~level ~timestamp =
   Raw_context.prepare_first_block ~level ~timestamp ctxt
   >>=? fun (previous_protocol, ctxt) ->
   let parametric = Raw_context.constants ctxt in
@@ -166,7 +186,7 @@ let prepare_first_block _chain_id ctxt ~typecheck ~level ~timestamp =
       Storage.Tenderbake.First_level_of_protocol.update ctxt level
       >>=? fun ctxt ->
       Delegate_cycles.Migration_from_Kathmandu.update ctxt >>=? fun ctxt ->
-      return (ctxt, []))
+      Patch_ghostnet.patch chain_id ctxt level >>=? fun ctxt -> return (ctxt, []))
   >>=? fun (ctxt, balance_updates) ->
   List.fold_right_es patch_script Legacy_script_patches.addresses_to_patch ctxt
   >>=? fun ctxt ->
diff --git a/tezt/tests/ghostnet_dictator_migration.ml b/tezt/tests/ghostnet_dictator_migration.ml
index 1b19650891bac47a618aac084c0fed891da65241..660521f74f0117c379db1fca960657148031d5c3 100644
--- a/tezt/tests/ghostnet_dictator_migration.ml
+++ b/tezt/tests/ghostnet_dictator_migration.ml
@@ -53,7 +53,7 @@ let check_dictator client expected_dictator =
   unit
 
 let init chain_id ~from_protocol ~to_protocol =
-  let user_activated_upgrades = [(3, to_protocol)] in
+  let user_activated_upgrades = [(11, to_protocol)] in
   let patch_config, timestamp =
     match chain_id with
     | Chain_id_mainnet ->
@@ -107,33 +107,46 @@ let register_migration_test chain_id =
   @@ fun to_protocol ->
   may_apply (Protocol.previous_protocol to_protocol) @@ fun from_protocol ->
   let* node, client = init chain_id ~from_protocol ~to_protocol in
-  let* () = bake node client in
-  let* () = bake node client in
+  let* () = repeat 10 (fun () -> bake node client) in
   Log.info "Checking that migration occurred..." ;
   let* () =
     Voting.check_protocols
       client
       (Protocol.hash from_protocol, Protocol.hash to_protocol)
   in
-  let expected_dictator, expected_remaining =
+  let expected_dictator, expected_period =
     match chain_id with
     | Chain_id_ghostnet when to_protocol = Kathmandu ->
-        (Some "tz1Xf8zdT3DbAX9cHw3c3CXh79rc4nK4gCe8", 1)
-    | _ -> (None, 5)
+        ( Some "tz1Xf8zdT3DbAX9cHw3c3CXh79rc4nK4gCe8",
+          {
+            Voting.index = 1;
+            kind = Proposal;
+            start_position = 8;
+            position = 2;
+            remaining = 1;
+          } )
+    | Chain_id_ghostnet when to_protocol = Alpha ->
+        ( None,
+          {
+            Voting.index = 1;
+            kind = Proposal;
+            start_position = 3;
+            position = 7;
+            remaining = 0;
+          } )
+    | _ ->
+        ( None,
+          {
+            Voting.index = 1;
+            kind = Proposal;
+            start_position = 8;
+            position = 2;
+            remaining = 5;
+          } )
   in
 
   let* () = check_dictator client expected_dictator in
-  let* () =
-    Voting.check_current_period
-      client
-      {
-        Voting.index = 0;
-        kind = Proposal;
-        start_position = 0;
-        position = 2;
-        remaining = expected_remaining;
-      }
-  in
+  let* () = Voting.check_current_period client expected_period in
   return ()
 
 let register ~protocols =