diff --git a/apps/gitgud/lib/gitgud/ssh_server.ex b/apps/gitgud/lib/gitgud/ssh_server.ex
index 568c3a5b..71c40453 100644
--- a/apps/gitgud/lib/gitgud/ssh_server.ex
+++ b/apps/gitgud/lib/gitgud/ssh_server.ex
@@ -89,8 +89,13 @@ defmodule GitGud.SSHServer do
   @impl true
   def handle_ssh_msg({:ssh_cm, conn, {:data, chan, _type, data}}, %__MODULE__{conn: conn, chan: chan, exec: exec} = state) do
     {exec, io} = Service.next(exec, data)
-    if io, do: :ssh_connection.send(conn, chan, io)
-    if Service.done?(exec), do: :ssh_connection.close(conn, chan)
+    :ssh_connection.send(conn, chan, io)
+    if Service.done?(exec) do
+      :ssh_connection.send_eof(conn, chan)
+      :ssh_connection.exit_status(conn, chan, 0)
+      :ssh_connection.close(conn, chan)
+    end
+
     {:ok, %{state|exec: exec}}
   end
 
diff --git a/apps/gitrekt/lib/gitrekt/packfile.ex b/apps/gitrekt/lib/gitrekt/packfile.ex
index 5a8aa1cc..c5d10cc1 100644
--- a/apps/gitrekt/lib/gitrekt/packfile.ex
+++ b/apps/gitrekt/lib/gitrekt/packfile.ex
@@ -13,11 +13,11 @@ defmodule GitRekt.Packfile do
   @doc """
   Returns a *PACK* file for the given `oids` list.
   """
-  @spec create(Git.repo, [Git.oid]) :: binary
+  @spec create(Git.repo, [Git.oid|{Git.oid, boolean}]) :: binary
   def create(repo, oids) when is_list(oids) do
     with {:ok, pack} <- Git.pack_new(repo),
          {:ok, walk} <- Git.revwalk_new(repo),
-          :ok <- pack_insert(pack, walk, oids),
+          :ok <- pack_insert(pack, walk, oid_mask(oids)),
          {:ok, data} <- Git.pack_data(pack), do: data
   end
 
@@ -32,15 +32,30 @@ defmodule GitRekt.Packfile do
   # Helpers
   #
 
-  defp unpack(2 = _version, count, data) do
-    unpack_obj_next(0, count, data, [])
+  defp pack_insert(pack, walk, oids) do
+    case walk_insert(walk, oids) do
+      :ok -> Git.pack_insert_walk(pack, walk)
+      {:error, reason} -> {:error, reason}
+    end
+  end
+
+  defp walk_insert(_walk, []), do: :ok
+  defp walk_insert(walk, [{oid, hide}|oids]) do
+    case Git.revwalk_push(walk, oid, hide) do
+      :ok -> walk_insert(walk, oids)
+      {:error, reason} -> {:error, reason}
+    end
+  end
+
+  defp oid_mask(oids) do
+    Enum.map(oids, fn
+      {oid, hidden} when is_binary(oid) -> {oid, hidden}
+      oid when is_binary(oid) -> {oid, false}
+    end)
   end
 
-  defp pack_insert(_pack, _walk, []), do: :ok
-  defp pack_insert(pack, walk, [oid|oids]) do
-    with :ok <- Git.revwalk_push(walk, oid),
-         :ok <- Git.pack_insert_walk(pack, walk),
-         :ok <- Git.revwalk_reset(walk), do: pack_insert(pack, walk, oids)
+  defp unpack(2 = _version, count, data) do
+    unpack_obj_next(0, count, data, [])
   end
 
   defp unpack_obj_next(i, max, rest, acc) when i < max do
diff --git a/apps/gitrekt/lib/gitrekt/wire_protocol.ex b/apps/gitrekt/lib/gitrekt/wire_protocol.ex
index 32d0d8fe..27c03080 100644
--- a/apps/gitrekt/lib/gitrekt/wire_protocol.ex
+++ b/apps/gitrekt/lib/gitrekt/wire_protocol.ex
@@ -6,7 +6,7 @@ defmodule GitRekt.WireProtocol do
   alias GitRekt.Git
   alias GitRekt.Packfile
 
-  @upload_caps ~w()
+  @upload_caps ~w(multi_ack multi_ack_detailed)
   @receive_caps ~w(report-status delete-refs)
 
   @doc """
@@ -43,6 +43,8 @@ defmodule GitRekt.WireProtocol do
   @spec pkt_line(binary|:flush) :: binary
   def pkt_line(data \\ :flush)
   def pkt_line(:flush), do: "0000"
+  def pkt_line({:ack, oid}), do: pkt_line("ACK #{Git.oid_fmt(oid)}")
+  def pkt_line({:ack, oid, status}), do: pkt_line("ACK #{Git.oid_fmt(oid)} #{status}")
   def pkt_line(:nak), do: pkt_line("NAK")
   def pkt_line(<<"PACK", _rest::binary>> = pack), do: pack
   def pkt_line(data) when is_binary(data) do
diff --git a/apps/gitrekt/lib/gitrekt/wire_protocol/receive_pack.ex b/apps/gitrekt/lib/gitrekt/wire_protocol/receive_pack.ex
index 2c07822f..6393997c 100644
--- a/apps/gitrekt/lib/gitrekt/wire_protocol/receive_pack.ex
+++ b/apps/gitrekt/lib/gitrekt/wire_protocol/receive_pack.ex
@@ -11,6 +11,8 @@ defmodule GitRekt.WireProtocol.ReceivePack do
 
   defstruct [:repo, state: :disco, caps: [], cmds: [], pack: []]
 
+  @null_oid String.duplicate("0", 40)
+
   @type cmd :: {
     :create | :update | :delete,
     Git.oid,
@@ -73,23 +75,26 @@ defmodule GitRekt.WireProtocol.ReceivePack do
   def run(%__MODULE__{state: :pack} = handle) do
     :ok = apply_pack(handle.repo, handle.pack)
     :ok = apply_cmds(handle.repo, handle.cmds)
-    handle = struct(handle, state: :done)
-    if "report-status" in handle.caps,
-      do: {handle, report_status(handle.cmds)},
-    else: {handle, []}
+    run(struct(handle, state: :done))
   end
 
   @impl true
-  def run(%__MODULE__{state: :done} = handle) do
+  def run(%__MODULE__{state: :done, cmds: []} = handle) do
     {handle, []}
   end
 
+  def run(%__MODULE__{state: :done} = handle) do
+    if "report-status" in handle.caps,
+      do: {handle, report_status(handle.cmds)},
+    else: {handle, []}
+  end
+
   #
   # Helpers
   #
 
   defp report_status(cmds) do
-    List.flatten(["unpack ok", Enum.map(cmds, &"ok #{elem(&1, 3)}"), :flush])
+    List.flatten(["unpack ok", Enum.map(cmds, &"ok #{elem(&1, :erlang.tuple_size(&1)-1)}"), :flush])
   end
 
   defp obj_match?({type, _oid}, type), do: true
@@ -97,7 +102,11 @@ defmodule GitRekt.WireProtocol.ReceivePack do
 
   defp parse_cmds(cmds) do
     Enum.map(cmds, fn cmd ->
-      case String.split(cmd) do
+      case String.split(cmd, " ", parts: 3) do
+        [@null_oid, new, name] ->
+          {:create, Git.oid_parse(new), name}
+        [old, @null_oid, name] ->
+          {:delete, Git.oid_parse(old), name}
         [old, new, name] ->
           {:update, Git.oid_parse(old), Git.oid_parse(new), name}
       end
@@ -114,7 +123,9 @@ defmodule GitRekt.WireProtocol.ReceivePack do
 
   defp apply_cmds(repo, cmds) do
     Enum.each(cmds, fn
+      {:create, new_oid, refname} -> Git.reference_create(repo, refname, :oid, new_oid, false)
       {:update, _old_oid, new_oid, refname} -> Git.reference_create(repo, refname, :oid, new_oid, true)
+    # {:delete, old_oid, refname} -> Git.reference_delete(repo, refname, :oid, old_oid)
     end)
   end
 
diff --git a/apps/gitrekt/lib/gitrekt/wire_protocol/service.ex b/apps/gitrekt/lib/gitrekt/wire_protocol/service.ex
index 9ddc70bd..1b06be4d 100644
--- a/apps/gitrekt/lib/gitrekt/wire_protocol/service.ex
+++ b/apps/gitrekt/lib/gitrekt/wire_protocol/service.ex
@@ -39,7 +39,7 @@ defmodule GitRekt.WireProtocol.Service do
   @spec flush(Module.t) :: {Module.t, iolist}
   def flush(service) do
     case apply(service.__struct__, :run, [service]) do
-      {handle, []} -> {handle, nil}
+      {handle, []} -> {handle, []}
       {handle, io} -> {handle, encode(io)}
     end
   end
diff --git a/apps/gitrekt/lib/gitrekt/wire_protocol/upload_pack.ex b/apps/gitrekt/lib/gitrekt/wire_protocol/upload_pack.ex
index 2aa80301..740aab9d 100644
--- a/apps/gitrekt/lib/gitrekt/wire_protocol/upload_pack.ex
+++ b/apps/gitrekt/lib/gitrekt/wire_protocol/upload_pack.ex
@@ -39,14 +39,21 @@ defmodule GitRekt.WireProtocol.UploadPack do
   end
 
   @impl true
-  def next(%__MODULE__{state: :upload_wants} = handle, lines) do
-    {haves, lines} = Enum.split_while(lines, &obj_match?(&1, :have))
-    {struct(handle, state: :upload_haves, haves: parse_cmds(haves)), lines}
+  def next(%__MODULE__{state: :upload_wants} = handle, [:done]) do
+    {struct(handle, state: :done), []}
   end
 
   @impl true
-  def next(%__MODULE__{state: :upload_haves} = handle, [:done]) do
-    {handle, []}
+  def next(%__MODULE__{state: :upload_wants} = handle, lines) do
+    {:ok, odb} = Git.repository_get_odb(handle.repo)
+    {haves, lines} = Enum.split_while(lines, &obj_match?(&1, :have))
+    acks = Enum.filter(parse_cmds(haves), &Git.odb_object_exists?(odb, &1))
+    case lines do
+      [:flush|lines] ->
+        {struct(handle, haves: [acks|handle.haves]), lines}
+      [:done|lines] ->
+        {struct(handle, state: :upload_haves, haves: [acks|handle.haves]), lines}
+    end
   end
 
   @impl true
@@ -61,20 +68,61 @@ defmodule GitRekt.WireProtocol.UploadPack do
   end
 
   @impl true
-  def run(%__MODULE__{state: :upload_wants} = handle) do
+  def run(%__MODULE__{state: :upload_wants, haves: []} = handle) do
     {handle, []}
   end
 
+  @impl true
+  def run(%__MODULE__{state: :upload_wants} = handle) do
+    acks = ack_haves(handle.haves, handle.caps)
+    cond do
+      "multi_ack_detailed" in handle.caps ->
+        {handle, acks ++ [:nak]}
+      "multi_ack" in handle.caps ->
+        {handle, acks ++ [:nak]}
+      Enum.empty?(handle.haves) ->
+        {handle, [:nak]}
+      Enum.empty?(acks) ->
+        {handle, []}
+      true ->
+        {handle, [List.first(acks)]}
+    end
+  end
+
   @impl true
   def run(%__MODULE__{state: :upload_haves} = handle) do
-    {struct(handle, state: :done), [:nak, create(handle.repo, handle.wants)]}
+    {next, lines} = run(struct(handle, state: :done))
+    cond do
+      "multi_ack_detailed" in handle.caps ->
+        {next, ack_haves(handle.haves, handle.caps) ++ lines}
+      "multi_ack" in handle.caps ->
+        {next, ack_haves(handle.haves, handle.caps) ++ lines}
+      true ->
+        {next, lines}
+    end
   end
 
   @impl true
-  def run(%__MODULE__{state: :done} = handle) do
+  def run(%__MODULE__{state: :done, wants: [], haves: []} = handle) do
     {handle, []}
   end
 
+  def run(%__MODULE__{state: :done, haves: []} = handle) do
+    {handle, [:nak, create(handle.repo, handle.wants)]}
+  end
+
+  def run(%__MODULE__{state: :done} = handle) do
+    [have|_] = List.flatten(Enum.reverse(handle.haves)) # TODO
+    cond do
+      "multi_ack_detailed" in handle.caps ->
+        {handle, [{:ack, have}, create(handle.repo, handle.wants ++ [{have, true}])]}
+      "multi_ack" in handle.caps ->
+        {handle, [{:ack, have}, create(handle.repo, handle.wants ++ [{have, true}])]}
+      true ->
+        {handle, [create(handle.repo, handle.wants ++ [{have, true}])]}
+    end
+  end
+
   #
   # Helpers
   #
@@ -86,9 +134,23 @@ defmodule GitRekt.WireProtocol.UploadPack do
 
   defp parse_caps([]), do: {[], []}
   defp parse_caps([{obj_type, first_ref}|wants]) do
-    case String.split(first_ref, "\0", parts: 2) do
+    case String.split(first_ref, " ", parts: 2) do
       [first_ref]       -> {[], [{obj_type, first_ref}|wants]}
       [first_ref, caps] -> {String.split(caps, " ", trim: true), [{obj_type, first_ref}|wants]}
     end
   end
+
+  defp ack_haves([], _caps), do: []
+  defp ack_haves([haves|_], caps) do
+    cond do
+      "multi_ack_detailed" in caps ->
+        Enum.map(haves, &{:ack, &1, :common})
+      "multi_ack" in caps ->
+        Enum.map(haves, &{:ack, &1, :continue})
+      [have|_] = haves ->
+        [{:ack, have}]
+      true ->
+        []
+    end
+  end
 end