diff --git a/src/CommandFormats.hh b/src/CommandFormats.hh
index 7ea102f1..a36e7607 100644
--- a/src/CommandFormats.hh
+++ b/src/CommandFormats.hh
@@ -301,6 +301,8 @@ struct S_Reconnect_Patch_14 : S_Reconnect<be_uint16_t> {
 // player why they can't do something (e.g. join a full game).
 // This format is shared by multiple commands; for all of them except 06 (S->C),
 // the guild_card_number field is unused and should be 0.
+// On BB, this command may be sent as 0001 or 0101; in the latter case, the
+// message box appears in the lower-left corner instead.
 
 struct SC_TextHeader_01_06_11_B0_EE {
   le_uint32_t unused = 0;
@@ -3490,7 +3492,8 @@ struct S_CardTradeComplete_GC_Ep3_EE_FlagD4 {
 
 // EE (S->C): Scrolling message (BB)
 // Same format as 01. The message appears at the top of the screen and slowly
-// scrolls to the left.
+// scrolls to the left. The maximum length of the message is 0x400 bytes (0x200
+// UTF-16 characters).
 
 // EF (C->S): Join card auction (Episode 3)
 // When a card auction is ready to begin, the leader sends this command to
diff --git a/src/SendCommands.cc b/src/SendCommands.cc
index b002020a..3d604696 100644
--- a/src/SendCommands.cc
+++ b/src/SendCommands.cc
@@ -789,8 +789,9 @@ void send_quest_info(shared_ptr<Client> c, const string& text, bool is_download_
       c->config.check_flag(Client::Flag::IS_DC_TRIAL_EDITION) ? ColorMode::STRIP : ColorMode::ADD);
 }
 
-void send_lobby_message_box(shared_ptr<Client> c, const string& text) {
-  send_header_text(c->channel, 0x01, 0, text, c->config.check_flag(Client::Flag::IS_DC_TRIAL_EDITION) ? ColorMode::STRIP : ColorMode::ADD);
+void send_lobby_message_box(shared_ptr<Client> c, const string& text, bool left_side_on_bb) {
+  uint16_t command = (left_side_on_bb && (c->version() == GameVersion::BB)) ? 0x0101 : 0x0001;
+  send_header_text(c->channel, command, 0, text, c->config.check_flag(Client::Flag::IS_DC_TRIAL_EDITION) ? ColorMode::STRIP : ColorMode::ADD);
 }
 
 void send_ship_info(shared_ptr<Client> c, const string& text) {
diff --git a/src/SendCommands.hh b/src/SendCommands.hh
index f5620404..33192df2 100644
--- a/src/SendCommands.hh
+++ b/src/SendCommands.hh
@@ -179,7 +179,7 @@ void send_ep3_timed_message_box(Channel& ch, uint32_t frames, const std::string&
 void send_lobby_name(std::shared_ptr<Client> c, const std::string& text);
 void send_quest_info(std::shared_ptr<Client> c, const std::string& text,
     bool is_download_quest);
-void send_lobby_message_box(std::shared_ptr<Client> c, const std::string& text);
+void send_lobby_message_box(std::shared_ptr<Client> c, const std::string& text, bool left_side_on_bb = false);
 void send_ship_info(std::shared_ptr<Client> c, const std::string& text);
 void send_ship_info(Channel& ch, const std::string& text);
 void send_text_message(Channel& ch, const std::string& text);