diff --git a/simulation/halsim_ds_socket/src/main/native/cpp/DSCommPacket.cpp b/simulation/halsim_ds_socket/src/main/native/cpp/DSCommPacket.cpp
index 92f1720772..ead2534d68 100644
--- a/simulation/halsim_ds_socket/src/main/native/cpp/DSCommPacket.cpp
+++ b/simulation/halsim_ds_socket/src/main/native/cpp/DSCommPacket.cpp
@@ -96,7 +96,7 @@ void DSCommPacket::ReadJoystickTag(wpi::ArrayRef<uint8_t> dataInput,
   int numBytes = (buttonCount + 7) / 8;
   stick.buttons.buttons = 0;
   for (int i = 0; i < numBytes; i++) {
-    stick.buttons.buttons |= dataInput[1 + i] << (8 * (i));
+    stick.buttons.buttons |= dataInput[numBytes - i] << (8 * (i));
   }
   stick.buttons.count = buttonCount;
 
diff --git a/simulation/halsim_ds_socket/src/test/native/cpp/DSCommPacketTest.cpp b/simulation/halsim_ds_socket/src/test/native/cpp/DSCommPacketTest.cpp
index a72aafcc0c..91190fba19 100644
--- a/simulation/halsim_ds_socket/src/test/native/cpp/DSCommPacketTest.cpp
+++ b/simulation/halsim_ds_socket/src/test/native/cpp/DSCommPacketTest.cpp
@@ -66,13 +66,21 @@ TEST_F(DSCommPacketTest, BlankJoystickTag) {
 
 TEST_F(DSCommPacketTest, MainJoystickTag) {
   for (int i = 0; i < HAL_kMaxJoysticks; i++) {
+    // Just random data
+    std::array<uint8_t, 12> _buttons{0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1};
+
+    std::array<uint8_t, 2> _button_bytes{0, 0};
+    for (int btn = 0; btn < 8; btn++) _button_bytes[1] |= _buttons[btn] << btn;
+    for (int btn = 8; btn < 12; btn++)
+      _button_bytes[0] |= _buttons[btn] << (btn - 8);
+
     // 5 for base, 4 joystick, 12 buttons (2 bytes) 3 povs
     uint8_t arr[5 + 4 + 2 + 6] = {// Size, Tag
                                   16, 12,
                                   // Axes
                                   4, 0x9C, 0xCE, 0, 75,
-                                  // Buttons
-                                  12, 0xFF, 0x0F,
+                                  // Buttons (LSB 0)
+                                  12, _button_bytes[0], _button_bytes[1],
                                   // POVs
                                   3, 0, 50, 0, 100, 0x0F, 0x00};
 
@@ -80,6 +88,11 @@ TEST_F(DSCommPacketTest, MainJoystickTag) {
     ASSERT_EQ(data.axes.count, 4);
     ASSERT_EQ(data.povs.count, 3);
     ASSERT_EQ(data.buttons.count, 12);
+
+    for (int btn = 0; btn < 12; btn++) {
+      ASSERT_EQ((data.buttons.buttons & (1 << btn)) != 0, _buttons[btn] != 0)
+          << "Button " << btn;
+    }
   }
 }