diff --git a/glass/src/lib/native/cpp/other/FMS.cpp b/glass/src/lib/native/cpp/other/FMS.cpp
index 67c3f8c904..d49304e039 100644
--- a/glass/src/lib/native/cpp/other/FMS.cpp
+++ b/glass/src/lib/native/cpp/other/FMS.cpp
@@ -14,7 +14,7 @@ using namespace glass;
 static const char* stations[] = {"Invalid", "Red 1",  "Red 2", "Red 3",
                                  "Blue 1",  "Blue 2", "Blue 3"};
 
-void glass::DisplayFMS(FMSModel* model) {
+void glass::DisplayFMS(FMSModel* model, bool editableDsAttached) {
   if (!model->Exists() || model->IsReadOnly()) {
     return DisplayFMSReadOnly(model);
   }
@@ -31,10 +31,17 @@ void glass::DisplayFMS(FMSModel* model) {
   // DS Attached
   if (auto data = model->GetDsAttachedData()) {
     bool val = data->GetValue();
-    if (ImGui::Checkbox("DS Attached", &val)) {
-      model->SetDsAttached(val);
+    if (editableDsAttached) {
+      if (ImGui::Checkbox("DS Attached", &val)) {
+        model->SetDsAttached(val);
+      }
+      data->EmitDrag();
+    } else {
+      ImGui::Selectable("DS Attached: ");
+      data->EmitDrag();
+      ImGui::SameLine();
+      ImGui::TextUnformatted(val ? "Yes" : "No");
     }
-    data->EmitDrag();
   }
 
   // Alliance Station
diff --git a/glass/src/lib/native/include/glass/other/FMS.h b/glass/src/lib/native/include/glass/other/FMS.h
index 5970e93e22..f039c15a70 100644
--- a/glass/src/lib/native/include/glass/other/FMS.h
+++ b/glass/src/lib/native/include/glass/other/FMS.h
@@ -46,8 +46,9 @@ class FMSModel : public Model {
  *
  * @param matchTimeEnabled If not null, a checkbox is displayed for
  *                         "enable match time" linked to this value
+ * @param editableDsAttached If true, DS attached should be editable
  */
-void DisplayFMS(FMSModel* model);
+void DisplayFMS(FMSModel* model, bool editableDsAttached);
 void DisplayFMSReadOnly(FMSModel* model);
 
 }  // namespace glass
diff --git a/glass/src/libnt/native/cpp/StandardNetworkTables.cpp b/glass/src/libnt/native/cpp/StandardNetworkTables.cpp
index 9031873ad8..4cc2121269 100644
--- a/glass/src/libnt/native/cpp/StandardNetworkTables.cpp
+++ b/glass/src/libnt/native/cpp/StandardNetworkTables.cpp
@@ -63,7 +63,7 @@ void glass::AddStandardNetworkTablesViews(NetworkTablesProvider& provider) {
       [](Window* win, Model* model, const char*) {
         win->SetFlags(ImGuiWindowFlags_AlwaysAutoResize);
         return MakeFunctionView(
-            [=] { DisplayFMS(static_cast<FMSModel*>(model)); });
+            [=] { DisplayFMS(static_cast<FMSModel*>(model), true); });
       });
   provider.Register(
       NTDigitalInputModel::kType,
diff --git a/hal/src/main/native/sim/DriverStation.cpp b/hal/src/main/native/sim/DriverStation.cpp
index 67b2eb728a..b245eed59d 100644
--- a/hal/src/main/native/sim/DriverStation.cpp
+++ b/hal/src/main/native/sim/DriverStation.cpp
@@ -382,6 +382,7 @@ void NewDriverStationData() {
   }
   lastGiven = given;
 
+  SimDriverStationData->dsAttached = true;
   driverStation->newDataEvents.Wakeup();
   SimDriverStationData->CallNewDataCallbacks();
 }
diff --git a/hal/src/main/native/sim/mockdata/DriverStationData.cpp b/hal/src/main/native/sim/mockdata/DriverStationData.cpp
index a0cae1c9a2..d124b21308 100644
--- a/hal/src/main/native/sim/mockdata/DriverStationData.cpp
+++ b/hal/src/main/native/sim/mockdata/DriverStationData.cpp
@@ -28,7 +28,7 @@ void DriverStationData::ResetData() {
   test.Reset(false);
   eStop.Reset(false);
   fmsAttached.Reset(false);
-  dsAttached.Reset(true);
+  dsAttached.Reset(false);
   allianceStationId.Reset(static_cast<HAL_AllianceStationID>(0));
   matchTime.Reset(-1.0);
 
diff --git a/hal/src/main/native/sim/mockdata/DriverStationDataInternal.h b/hal/src/main/native/sim/mockdata/DriverStationDataInternal.h
index 763b465f32..008329fde8 100644
--- a/hal/src/main/native/sim/mockdata/DriverStationDataInternal.h
+++ b/hal/src/main/native/sim/mockdata/DriverStationDataInternal.h
@@ -122,7 +122,7 @@ class DriverStationData {
   SimDataValue<HAL_Bool, HAL_MakeBoolean, GetEStopName> eStop{false};
   SimDataValue<HAL_Bool, HAL_MakeBoolean, GetFmsAttachedName> fmsAttached{
       false};
-  SimDataValue<HAL_Bool, HAL_MakeBoolean, GetDsAttachedName> dsAttached{true};
+  SimDataValue<HAL_Bool, HAL_MakeBoolean, GetDsAttachedName> dsAttached{false};
   SimDataValue<HAL_AllianceStationID, MakeAllianceStationIdValue,
                GetAllianceStationIdName>
       allianceStationId{static_cast<HAL_AllianceStationID>(0)};
diff --git a/simulation/halsim_gui/src/main/native/cpp/DriverStationGui.cpp b/simulation/halsim_gui/src/main/native/cpp/DriverStationGui.cpp
index 09192f39ff..42df53efea 100644
--- a/simulation/halsim_gui/src/main/native/cpp/DriverStationGui.cpp
+++ b/simulation/halsim_gui/src/main/native/cpp/DriverStationGui.cpp
@@ -227,37 +227,25 @@ class FMSSimModel : public glass::FMSModel {
   glass::DataSource* GetAutonomousData() override { return &m_autonomous; }
   std::string_view GetGameSpecificMessage(
       wpi::SmallVectorImpl<char>& buf) override {
-    HAL_MatchInfo info;
-    HALSIM_GetMatchInfo(&info);
-    buf.clear();
-    buf.append(info.gameSpecificMessage,
-               info.gameSpecificMessage + info.gameSpecificMessageSize);
-    return std::string_view(buf.begin(), buf.size());
+    return m_gameMessage;
   }
 
-  void SetFmsAttached(bool val) override {
-    HALSIM_SetDriverStationFmsAttached(val);
-  }
-  void SetDsAttached(bool val) override {
-    HALSIM_SetDriverStationDsAttached(val);
-  }
+  void SetFmsAttached(bool val) override { m_fmsAttached.SetValue(val); }
+  void SetDsAttached(bool val) override { m_dsAttached.SetValue(val); }
   void SetAllianceStationId(int val) override {
-    HALSIM_SetDriverStationAllianceStationId(
-        static_cast<HAL_AllianceStationID>(val));
-  }
-  void SetMatchTime(double val) override {
-    HALSIM_SetDriverStationMatchTime(val);
-  }
-  void SetEStop(bool val) override { HALSIM_SetDriverStationEStop(val); }
-  void SetEnabled(bool val) override { HALSIM_SetDriverStationEnabled(val); }
-  void SetTest(bool val) override { HALSIM_SetDriverStationTest(val); }
-  void SetAutonomous(bool val) override {
-    HALSIM_SetDriverStationAutonomous(val);
+    m_allianceStationId.SetValue(val);
   }
+  void SetMatchTime(double val) override { m_matchTime.SetValue(val); }
+  void SetEStop(bool val) override { m_estop.SetValue(val); }
+  void SetEnabled(bool val) override { m_enabled.SetValue(val); }
+  void SetTest(bool val) override { m_test.SetValue(val); }
+  void SetAutonomous(bool val) override { m_autonomous.SetValue(val); }
   void SetGameSpecificMessage(std::string_view val) override {
-    HALSIM_SetGameSpecificMessage(val.data(), val.size());
+    m_gameMessage = val;
   }
 
+  void UpdateHAL();
+
   void Update() override;
 
   bool Exists() override { return true; }
@@ -274,6 +262,7 @@ class FMSSimModel : public glass::FMSModel {
   glass::DataSource m_test{"FMS:TestMode"};
   glass::DataSource m_autonomous{"FMS:AutonomousMode"};
   double m_startMatchTime = -1.0;
+  std::string m_gameMessage;
 };
 
 }  // namespace
@@ -1019,6 +1008,21 @@ void RobotJoystick::GetHAL(int i) {
   HALSIM_GetJoystickPOVs(i, &data.povs);
 }
 
+static void DriverStationConnect(bool enabled, bool autonomous, bool test) {
+  if (!HALSIM_GetDriverStationDsAttached()) {
+    // initialize FMS bits too
+    gFMSModel->SetDsAttached(true);
+    gFMSModel->SetEnabled(enabled);
+    gFMSModel->SetAutonomous(autonomous);
+    gFMSModel->SetTest(test);
+    gFMSModel->UpdateHAL();
+  } else {
+    HALSIM_SetDriverStationEnabled(enabled);
+    HALSIM_SetDriverStationAutonomous(autonomous);
+    HALSIM_SetDriverStationTest(test);
+  }
+}
+
 static void DriverStationExecute() {
   // update sources
   for (int i = 0; i < HAL_kMaxJoysticks; ++i) {
@@ -1072,6 +1076,7 @@ static void DriverStationExecute() {
     joy.Update();
   }
 
+  bool isAttached = HALSIM_GetDriverStationDsAttached();
   bool isEnabled = HALSIM_GetDriverStationEnabled();
   bool isAuto = HALSIM_GetDriverStationAutonomous();
   bool isTest = HALSIM_GetDriverStationTest();
@@ -1100,38 +1105,45 @@ static void DriverStationExecute() {
 
     ImGui::SetNextWindowPos(ImVec2{5, 20}, ImGuiCond_FirstUseEver);
     ImGui::Begin("Robot State", nullptr, ImGuiWindowFlags_AlwaysAutoResize);
-    if (ImGui::Selectable("Disabled", !isEnabled) || disableHotkey) {
+    if (ImGui::Selectable("Disconnected", !isAttached)) {
       HALSIM_SetDriverStationEnabled(false);
+      HALSIM_SetDriverStationDsAttached(false);
+      isAttached = false;
+      gFMSModel->Update();
     }
-    if (ImGui::Selectable("Autonomous", isEnabled && isAuto && !isTest)) {
-      HALSIM_SetDriverStationAutonomous(true);
-      HALSIM_SetDriverStationTest(false);
-      HALSIM_SetDriverStationEnabled(true);
+    if (ImGui::Selectable("Disabled", isAttached && !isEnabled) ||
+        disableHotkey) {
+      DriverStationConnect(false, false, false);
     }
-    if (ImGui::Selectable("Teleoperated", isEnabled && !isAuto && !isTest) ||
+    if (ImGui::Selectable("Autonomous",
+                          isAttached && isEnabled && isAuto && !isTest)) {
+      DriverStationConnect(true, true, false);
+    }
+    if (ImGui::Selectable("Teleoperated",
+                          isAttached && isEnabled && !isAuto && !isTest) ||
         enableHotkey) {
-      HALSIM_SetDriverStationAutonomous(false);
-      HALSIM_SetDriverStationTest(false);
-      HALSIM_SetDriverStationEnabled(true);
+      DriverStationConnect(true, false, false);
     }
     if (ImGui::Selectable("Test", isEnabled && isTest)) {
-      HALSIM_SetDriverStationAutonomous(false);
-      HALSIM_SetDriverStationTest(true);
-      HALSIM_SetDriverStationEnabled(true);
+      DriverStationConnect(true, false, true);
     }
     ImGui::End();
   }
 
   // Update HAL
-  for (int i = 0, end = gRobotJoysticks.size();
-       i < end && i < HAL_kMaxJoysticks; ++i) {
-    gRobotJoysticks[i].SetHAL(i);
+  if (isAttached) {
+    for (int i = 0, end = gRobotJoysticks.size();
+         i < end && i < HAL_kMaxJoysticks; ++i) {
+      gRobotJoysticks[i].SetHAL(i);
+    }
   }
 
   // Send new data every 20 ms (may be slower depending on GUI refresh rate)
   static double lastNewDataTime = 0.0;
-  if ((curTime - lastNewDataTime) > 0.02 && !HALSIM_IsTimingPaused()) {
+  if ((curTime - lastNewDataTime) > 0.02 && !HALSIM_IsTimingPaused() &&
+      isAttached) {
     lastNewDataTime = curTime;
+    gFMSModel->Update();
     HALSIM_NotifyDriverStationNewData();
   }
 }
@@ -1144,6 +1156,20 @@ FMSSimModel::FMSSimModel() {
   m_test.SetDigital(true);
   m_autonomous.SetDigital(true);
   m_matchTime.SetValue(-1.0);
+  m_allianceStationId.SetValue(HAL_AllianceStationID_kRed1);
+}
+
+void FMSSimModel::UpdateHAL() {
+  HALSIM_SetDriverStationFmsAttached(m_fmsAttached.GetValue());
+  HALSIM_SetDriverStationAllianceStationId(
+      static_cast<HAL_AllianceStationID>(m_allianceStationId.GetValue()));
+  HALSIM_SetDriverStationEStop(m_estop.GetValue());
+  HALSIM_SetDriverStationEnabled(m_enabled.GetValue());
+  HALSIM_SetDriverStationTest(m_test.GetValue());
+  HALSIM_SetDriverStationAutonomous(m_autonomous.GetValue());
+  HALSIM_SetDriverStationMatchTime(m_matchTime.GetValue());
+  HALSIM_SetGameSpecificMessage(m_gameMessage.data(), m_gameMessage.size());
+  HALSIM_SetDriverStationDsAttached(m_dsAttached.GetValue());
 }
 
 void FMSSimModel::Update() {
@@ -1176,6 +1202,11 @@ void FMSSimModel::Update() {
     m_startMatchTime = -1.0;
   }
   m_matchTime.SetValue(matchTime);
+
+  HAL_MatchInfo info;
+  HALSIM_GetMatchInfo(&info);
+  m_gameMessage.assign(info.gameSpecificMessage,
+                       info.gameSpecificMessage + info.gameSpecificMessageSize);
 }
 
 bool FMSSimModel::IsReadOnly() {
@@ -1387,7 +1418,6 @@ void DriverStationGui::GlobalInit() {
   gFMSModel = std::make_unique<FMSSimModel>();
 
   wpi::gui::AddEarlyExecute(DriverStationExecute);
-  wpi::gui::AddEarlyExecute([] { gFMSModel->Update(); });
 
   storageRoot.SetCustomApply([&storageRoot] {
     gpDisableDS = &storageRoot.GetBool("disable", false);
@@ -1433,8 +1463,13 @@ void DriverStationGui::GlobalInit() {
         win->SetDefaultSize(300, 560);
       }
     }
-    if (auto win =
-            dsManager->AddWindow("FMS", [] { DisplayFMS(gFMSModel.get()); })) {
+    if (auto win = dsManager->AddWindow("FMS", [] {
+          if (HALSIM_GetDriverStationDsAttached()) {
+            DisplayFMSReadOnly(gFMSModel.get());
+          } else {
+            DisplayFMS(gFMSModel.get(), false);
+          }
+        })) {
       win->DisableRenamePopup();
       win->SetFlags(ImGuiWindowFlags_AlwaysAutoResize);
       win->SetDefaultPos(5, 540);
diff --git a/wpilibc/src/test/native/cpp/simulation/DriverStationSimTest.cpp b/wpilibc/src/test/native/cpp/simulation/DriverStationSimTest.cpp
index 2513252893..8a5941ad37 100644
--- a/wpilibc/src/test/native/cpp/simulation/DriverStationSimTest.cpp
+++ b/wpilibc/src/test/native/cpp/simulation/DriverStationSimTest.cpp
@@ -104,15 +104,19 @@ TEST(DriverStationTest, FmsAttached) {
 TEST(DriverStationTest, DsAttached) {
   HAL_Initialize(500, 0);
   DriverStationSim::ResetData();
+  DriverStation::RefreshData();
 
+  EXPECT_FALSE(DriverStationSim::GetDsAttached());
+  EXPECT_FALSE(DriverStation::IsDSAttached());
   DriverStationSim::NotifyNewData();
+  EXPECT_TRUE(DriverStationSim::GetDsAttached());
   EXPECT_TRUE(DriverStation::IsDSAttached());
 
   BooleanCallback callback;
   auto cb = DriverStationSim::RegisterDsAttachedCallback(callback.GetCallback(),
                                                          false);
   DriverStationSim::SetDsAttached(false);
-  DriverStationSim::NotifyNewData();
+  DriverStation::RefreshData();
   EXPECT_FALSE(DriverStationSim::GetDsAttached());
   EXPECT_FALSE(DriverStation::IsDSAttached());
   EXPECT_TRUE(callback.WasTriggered());
diff --git a/wpilibj/src/test/java/edu/wpi/first/wpilibj/simulation/DriverStationSimTest.java b/wpilibj/src/test/java/edu/wpi/first/wpilibj/simulation/DriverStationSimTest.java
index 9a324d5153..54699e0036 100644
--- a/wpilibj/src/test/java/edu/wpi/first/wpilibj/simulation/DriverStationSimTest.java
+++ b/wpilibj/src/test/java/edu/wpi/first/wpilibj/simulation/DriverStationSimTest.java
@@ -108,14 +108,18 @@ class DriverStationSimTest {
   void testDsAttached() {
     HAL.initialize(500, 0);
     DriverStationSim.resetData();
+    DriverStation.refreshData();
 
+    assertFalse(DriverStationSim.getDsAttached());
+    assertFalse(DriverStation.isDSAttached());
     DriverStationSim.notifyNewData();
+    assertTrue(DriverStationSim.getDsAttached());
     assertTrue(DriverStation.isDSAttached());
 
     BooleanCallback callback = new BooleanCallback();
     try (CallbackStore cb = DriverStationSim.registerDsAttachedCallback(callback, false)) {
       DriverStationSim.setDsAttached(false);
-      DriverStationSim.notifyNewData();
+      DriverStation.refreshData();
       assertFalse(DriverStationSim.getDsAttached());
       assertFalse(DriverStation.isDSAttached());
       assertTrue(callback.wasTriggered());