diff --git a/prototype/tango-prototype/src/tango.erl b/prototype/tango-prototype/src/tango.erl
index 519f873..34e52c8 100644
--- a/prototype/tango-prototype/src/tango.erl
+++ b/prototype/tango-prototype/src/tango.erl
@@ -38,28 +38,28 @@
 
 %% TODO: for version 2: add strong checksum
 
-pack_v1(StreamList, Options, Page, PageSize)
-  when is_list(StreamList), is_list(Options), is_binary(Page),
+pack_v1(Stream_BackPs, Options, Page, PageSize)
+  when is_list(Stream_BackPs), is_list(Options), is_binary(Page),
        is_integer(PageSize), PageSize > 0 ->
-    StreamListBin = term_to_binary(StreamList),
-    StreamListSize = byte_size(StreamListBin),
+    Stream_BackPsBin = term_to_binary(Stream_BackPs),
+    Stream_BackPsSize = byte_size(Stream_BackPsBin),
     OptionsInt = convert_options_list2int(Options),
     PageActualSize = byte_size(Page),
     pad_bin(PageSize,
             list_to_binary([<<?MAGIC_NUMBER_V1:32/big>>,
                             <<OptionsInt:8/big>>,
-                            <<StreamListSize:16/big>>,
-                            StreamListBin,
+                            <<Stream_BackPsSize:16/big>>,
+                            Stream_BackPsBin,
                             <<PageActualSize:16/big>>,
                             Page])).
 
 unpack_v1(<<?MAGIC_NUMBER_V1:32/big,
             _Options:8/big,
-            StreamListSize:16/big, StreamListBin:StreamListSize/binary,
+            Stream_BackPsSize:16/big, Stream_BackPsBin:Stream_BackPsSize/binary,
             PageActualSize:16/big, Page:PageActualSize/binary,
             _/binary>>, Part) ->
     if Part == stream_list ->
-            binary_to_term(StreamListBin);
+            binary_to_term(Stream_BackPsBin);
        Part == page ->
             Page
     end.
@@ -102,11 +102,12 @@ scan_backward2(_Proj, _Stream, LastLPN, StopAtLPN, _NumPages, _WithPagesP)
   when LastLPN =< StopAtLPN; LastLPN =< 0 ->
     [];
 scan_backward2(Proj, Stream, LastLPN, StopAtLPN, NumPages, WithPagesP) ->
-    %% ?D({scan, lastlpn, LastLPN}),
+    ?D({scan, Stream, LastLPN}),
     case corfurl:read_page(Proj, LastLPN) of
         {ok, FullPage} ->
-            %% ?D({scan, LastLPN, ok}),
-            %% ?D({scan, Stream, unpack_v1(FullPage, stream_list)}),
+            ?D({scan, LastLPN, ok}),
+            ?D({scan, Stream, unpack_v1(FullPage, stream_list)}),
+?D(proplists:get_value(Stream, unpack_v1(FullPage, stream_list))),
             case proplists:get_value(Stream, unpack_v1(FullPage, stream_list)) of
                 undefined ->
                     if NumPages == 0 ->
@@ -123,11 +124,14 @@ scan_backward2(Proj, Stream, LastLPN, StopAtLPN, NumPages, WithPagesP) ->
                     end;
                 [] ->
                     if WithPagesP ->
+?D(?LINE),
                             [{LastLPN, unpack_v1(FullPage, page)}];
                        true ->
+?D(?LINE),
                             [LastLPN]
                     end;
                 BackPs ->
+?D(?LINE),
                     if WithPagesP ->
                             %% ?D({bummer, BackPs}),
                             [{LastLPN, unpack_v1(FullPage, page)}|
@@ -163,7 +167,8 @@ append_page(#proj{seq={Sequencer,_,_}, page_size=PageSize} = Proj,
         {ok, LPN, BackPsList} = corfurl_sequencer:get_tails(Sequencer, 1,
                                                             StreamList),
         %% pulse_tracing_add(write, LPN),
-        Page = tango:pack_v1(StreamList, [to_final_page],
+        StreamBackPs = lists:zip(StreamList, BackPsList),
+        Page = tango:pack_v1(StreamBackPs, [to_final_page],
                              OrigPage, PageSize),
         append_page1(Proj, LPN, Page, StreamList, 5, OrigPage)
     catch
diff --git a/prototype/tango-prototype/src/tango_oid.erl b/prototype/tango-prototype/src/tango_oid.erl
index 02ba712..17ca599 100644
--- a/prototype/tango-prototype/src/tango_oid.erl
+++ b/prototype/tango-prototype/src/tango_oid.erl
@@ -39,7 +39,7 @@
 
 -define(LONG_TIME, 30*1000).
 
--define(D(X), io:format(user, "Dbg: ~s =\n  ~p\n", [??X, X])).
+-define(D(X), io:format(user, "Dbg: ~s = ~p\n", [??X, X])).
 
 -type lpn() :: non_neg_integer().
 
@@ -143,6 +143,7 @@ fetch_unread_pages(Proj, LastLPN, StopAtLPN)
     %% ?D({fetch_unread_pages, LastLPN, StopAtLPN}),
     LPNandPages = tango:scan_backward(Proj, ?OID_STREAM_NUMBER, LastLPN,
                                       StopAtLPN, true),
+?D(LPNandPages),
     {_LPNs, _Pages} = lists:unzip(LPNandPages).
 
 play_log_pages(Pages, SideEffectsP,
@@ -155,8 +156,11 @@ play_log_pages(Pages, I_State, CallbackMod, SideEffectsP) ->
 
 roll_log_forward(#state{seq=SequencerPid, proj=Proj, all_back_ps=BackPs,
                         last_fetch_lpn=StopAtLPN} = State) ->
+?D(StopAtLPN),
     LastLPN = find_last_lpn(SequencerPid),
+?D(LastLPN),
     {LPNs, Pages} = fetch_unread_pages(Proj, LastLPN, StopAtLPN),
+?D(LPNs),
     NewBPs = append_lpns(LPNs, BackPs),
     play_log_pages(Pages, true, State#state{all_back_ps=NewBPs}).
 
@@ -193,15 +197,19 @@ play_log_mutate_i_state(Pages, SideEffectsP, I_State) ->
                         {Res, O2} =
                             case ?DICTMOD:find(Key, Dict) of
                                 error ->
+?D(?LINE),
                                     Dict2 = ?DICTMOD:store(Key, Next, Dict),
                                     {{ok, Next},O#oid_map{map=Dict2,
                                                           next=Next + 1}};
                                 {ok, _} ->
+?D(?LINE),
                                     {already_exists, O}
                             end,
                         if SideEffectsP ->
+?D(?LINE),
                                 gen_server:reply(From, Res);
                            true ->
+?D(?LINE),
                                 ok
                         end,
                         O2
diff --git a/prototype/tango-prototype/test/tango_oid_test.erl b/prototype/tango-prototype/test/tango_oid_test.erl
index 371714d..8e8046e 100644
--- a/prototype/tango-prototype/test/tango_oid_test.erl
+++ b/prototype/tango-prototype/test/tango_oid_test.erl
@@ -28,6 +28,8 @@
 -endif.
 -endif.
 
+-define(D(X), io:format(user, "Dbg: ~s = ~p\n", [??X, X])).
+
 -ifdef(TEST).
 -ifndef(PULSE).
 
@@ -52,8 +54,13 @@ tango_oid_one_test_int(PageSize, Seq, Proj) ->
         K1 = foo,
         K2 = bar,
         OID_Num1 = 1,
+        error = tango_oid:get(OID_Map, "does not exist"),
+
+?D(?LINE),
         {ok, OID_Num1} = tango_oid:new(OID_Map, K1),
+?D(?LINE),
         {ok, OID_Num1} = tango_oid:get(OID_Map, K1),
+?D(?LINE),
         already_exists = tango_oid:new(OID_Map, K1),
         %% The V2 put should *not* have clobbered the previous value
         {ok, OID_Num1} = tango_oid:get(OID_Map, K1),