diff --git a/src/kaleidoscope/Runtime.cpp b/src/kaleidoscope/Runtime.cpp
index 4f45f0c8..380ec63a 100644
--- a/src/kaleidoscope/Runtime.cpp
+++ b/src/kaleidoscope/Runtime.cpp
@@ -42,11 +42,7 @@ Runtime_::setup(void) {
 
   device().setup();
 
-  // Update the keymap cache, so we start with a non-empty state.
-  Layer.updateActiveLayers();
-  for (auto key_addr : KeyAddr::all()) {
-    Layer.updateLiveCompositeKeymap(key_addr);
-  }
+  Layer.setup();
 }
 
 void
diff --git a/src/kaleidoscope/layers.cpp b/src/kaleidoscope/layers.cpp
index af283773..48053d42 100644
--- a/src/kaleidoscope/layers.cpp
+++ b/src/kaleidoscope/layers.cpp
@@ -46,6 +46,17 @@ Key Layer_::live_composite_keymap_[Runtime.device().numKeys()];
 uint8_t Layer_::active_layer_keymap_[Runtime.device().numKeys()];
 Layer_::GetKeyFunction Layer_::getKey = &Layer_::getKeyFromPROGMEM;
 
+void Layer_::setup() {
+  // Explicitly set layer 0's state to 1
+  bitSet(layer_state_, 0);
+
+  // Update the keymap cache, so we start with a non-empty state.
+  Layer.updateActiveLayers();
+  for (auto key_addr : KeyAddr::all()) {
+    Layer.updateLiveCompositeKeymap(key_addr);
+  }
+}
+
 void Layer_::handleKeymapKeyswitchEvent(Key keymapEntry, uint8_t keyState) {
   if (keymapEntry.getKeyCode() >= LAYER_MOVE_OFFSET) {
     if (keyToggledOn(keyState)) {
diff --git a/src/kaleidoscope/layers.h b/src/kaleidoscope/layers.h
index 22ceb9cb..9b6175b9 100644
--- a/src/kaleidoscope/layers.h
+++ b/src/kaleidoscope/layers.h
@@ -51,6 +51,8 @@ class Layer_ {
  public:
   Layer_() {}
 
+  void setup();
+
   /* There are two lookup functions, because we have two caches, and different
    * parts of the firmware will want to use either this or that (or perhaps
    * both, in rare cases).
diff --git a/tests/issues/951/sketch.ino b/tests/issues/951/sketch.ino
new file mode 100644
index 00000000..2c6c5a76
--- /dev/null
+++ b/tests/issues/951/sketch.ino
@@ -0,0 +1,45 @@
+/* Kaleidoscope - Firmware for computer input devices
+ * Copyright (C) 2020  Keyboard.io, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "Kaleidoscope.h"
+
+// *INDENT-OFF*
+KEYMAPS(
+  [0] = KEYMAP_STACKED
+  (___,           Key_1, Key_2, Key_3, Key_4, Key_5, ___,
+   Key_Backtick,  Key_Q, Key_W, Key_E, Key_R, Key_T, Key_Tab,
+   Key_PageUp,    Key_A, Key_S, Key_D, Key_F, Key_G,
+   Key_PageDown,  Key_Z, Key_X, Key_C, Key_V, Key_B, Key_Escape,
+   Key_LeftControl, Key_Backspace, Key_LeftGui, Key_LeftShift,
+   ___,
+
+   ___,           Key_6, Key_7, Key_8,     Key_9,         Key_0,         ___,
+   Key_Enter,     Key_Y, Key_U, Key_I,     Key_O,         Key_P,         Key_Equals,
+                  Key_H, Key_J, Key_K,     Key_L,         Key_Semicolon, Key_Quote,
+   Key_RightAlt,  Key_N, Key_M, Key_Comma, Key_Period,    Key_Slash,     Key_Minus,
+   Key_RightShift, Key_LeftAlt, Key_Spacebar, Key_RightControl,
+   ___)
+)
+
+// *INDENT-ON*
+
+void setup() {
+  Kaleidoscope.setup();
+}
+
+void loop() {
+  Kaleidoscope.loop();
+}
diff --git a/tests/issues/951/test/testcase.cpp b/tests/issues/951/test/testcase.cpp
new file mode 100644
index 00000000..bd9a2e24
--- /dev/null
+++ b/tests/issues/951/test/testcase.cpp
@@ -0,0 +1,39 @@
+/* -*- mode: c++ -*-
+ * Copyright (C) 2020  Keyboard.io, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "Kaleidoscope.h"
+#include "testing/fix-macros.h"
+
+#include "testing/setup-googletest.h"
+
+SETUP_GOOGLETEST();
+
+namespace kaleidoscope {
+namespace testing {
+namespace {
+
+using ::testing::IsEmpty;
+
+class Issue951: public VirtualDeviceTest {};
+
+TEST_F(Issue951, InitialLayerState) {
+  EXPECT_THAT(Layer.isActive(0), true)
+      << "Layer 0 should be active when the keyboard starts up.";
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace kaleidoscope