diff --git a/src/audio/audio_fsm.cpp b/src/audio/audio_fsm.cpp
index e68eedaf..cd36b398 100644
--- a/src/audio/audio_fsm.cpp
+++ b/src/audio/audio_fsm.cpp
@@ -144,6 +144,8 @@ void Playback::exit() {
   // to drain.
   vTaskDelay(pdMS_TO_TICKS(250));
   sOutput->SetInUse(false);
+
+  events::System().Dispatch(PlaybackFinished{});
 }
 
 void Playback::react(const QueueUpdate& ev) {
diff --git a/src/audio/include/audio_events.hpp b/src/audio/include/audio_events.hpp
index 28e29863..1d3690a4 100644
--- a/src/audio/include/audio_events.hpp
+++ b/src/audio/include/audio_events.hpp
@@ -25,6 +25,8 @@ struct PlaybackUpdate : tinyfsm::Event {
   uint32_t seconds_total;
 };
 
+struct PlaybackFinished : tinyfsm::Event {};
+
 struct QueueUpdate : tinyfsm::Event {
   bool current_changed;
 };
diff --git a/src/system_fsm/idle.cpp b/src/system_fsm/idle.cpp
index 91075fc6..7cc1fa39 100644
--- a/src/system_fsm/idle.cpp
+++ b/src/system_fsm/idle.cpp
@@ -49,12 +49,17 @@ void Idle::exit() {
 }
 
 void Idle::react(const KeyLockChanged& ev) {
-  if (!ev.falling) {
+  if (ev.falling) {
     transit<Running>();
   }
 }
 
 void Idle::react(const internal::IdleTimeout& ev) {
+  if (!IdleCondition()) {
+    // Defensively ensure that we didn't miss an idle-ending event.
+    transit<Running>();
+    return;
+  }
   ESP_LOGI(kTag, "system shutting down");
 
   // FIXME: It would be neater to just free a bunch of our pointers, deinit the
@@ -79,7 +84,12 @@ void Idle::react(const internal::IdleTimeout& ev) {
 
   sGpios->Flush();
 
-  sSamd->PowerDown();
+  // Retry shutting down in case of a transient failure with the SAMD. e.g. i2c
+  // timeouts. This guards against a buggy SAMD firmware preventing idle.
+  for (;;) {
+    sSamd->PowerDown();
+    vTaskDelay(pdMS_TO_TICKS(1000));
+  }
 }
 
 }  // namespace states
diff --git a/src/system_fsm/include/system_fsm.hpp b/src/system_fsm/include/system_fsm.hpp
index 6baceca1..a556be9e 100644
--- a/src/system_fsm/include/system_fsm.hpp
+++ b/src/system_fsm/include/system_fsm.hpp
@@ -9,6 +9,7 @@
 #include <memory>
 
 #include "app_console.hpp"
+#include "audio_events.hpp"
 #include "battery.hpp"
 #include "bluetooth.hpp"
 #include "database.hpp"
@@ -54,9 +55,12 @@ class SystemState : public tinyfsm::Fsm<SystemState> {
   virtual void react(const StorageMounted&) {}
   virtual void react(const StorageError&) {}
   virtual void react(const KeyLockChanged&) {}
+  virtual void react(const audio::PlaybackFinished&) {}
   virtual void react(const internal::IdleTimeout&) {}
 
  protected:
+  auto IdleCondition() -> bool;
+
   static std::shared_ptr<drivers::Gpios> sGpios;
   static std::shared_ptr<drivers::Samd> sSamd;
   static std::shared_ptr<drivers::NvsStorage> sNvs;
@@ -101,6 +105,8 @@ class Running : public SystemState {
 
   void react(const KeyLockChanged&) override;
   void react(const StorageError&) override;
+  void react(const audio::PlaybackFinished&) override;
+
   using SystemState::react;
 };
 
diff --git a/src/system_fsm/running.cpp b/src/system_fsm/running.cpp
index 9e250c9b..3fc5493f 100644
--- a/src/system_fsm/running.cpp
+++ b/src/system_fsm/running.cpp
@@ -5,6 +5,7 @@
  */
 
 #include "app_console.hpp"
+#include "audio_events.hpp"
 #include "file_gatherer.hpp"
 #include "freertos/projdefs.h"
 #include "result.hpp"
@@ -68,7 +69,13 @@ void Running::exit() {
 }
 
 void Running::react(const KeyLockChanged& ev) {
-  if (!ev.falling && audio::AudioState::is_in_state<audio::states::Standby>()) {
+  if (IdleCondition()) {
+    transit<Idle>();
+  }
+}
+
+void Running::react(const audio::PlaybackFinished& ev) {
+  if (IdleCondition()) {
     transit<Idle>();
   }
 }
diff --git a/src/system_fsm/system_fsm.cpp b/src/system_fsm/system_fsm.cpp
index 78c4c53e..9ad89c7a 100644
--- a/src/system_fsm/system_fsm.cpp
+++ b/src/system_fsm/system_fsm.cpp
@@ -105,6 +105,11 @@ void SystemState::react(const internal::BatteryTimerFired&) {
   }
 }
 
+auto SystemState::IdleCondition() -> bool {
+  return !sGpios->Get(drivers::IGpios::Pin::kKeyLock) &&
+         audio::AudioState::is_in_state<audio::states::Standby>();
+}
+
 }  // namespace system_fsm
 
 FSM_INITIAL_STATE(system_fsm::SystemState, system_fsm::states::Booting)