diff --git a/main.c b/main.c
index da04ada466..378c506579 100755
--- a/main.c
+++ b/main.c
@@ -112,9 +112,6 @@ STATIC void start_mp(supervisor_allocation* heap) {
     reset_status_led();
     autoreload_stop();
     supervisor_workflow_reset();
-#if CIRCUITPY_ALARM
-    alarm_reset();
-#endif
 
     // Stack limit should be less than real stack size, so we have a chance
     // to recover from limit hit.  (Limit is measured in bytes.)
@@ -158,6 +155,13 @@ STATIC void start_mp(supervisor_allocation* heap) {
 
     mp_obj_list_init(mp_sys_argv, 0);
 
+    #if CIRCUITPY_ALARM
+    // Record which alarm woke us up, if any. An object may be created so the heap must be functional.
+    alarm_save_wakeup_alarm();
+    // Reset alarm module only after we retrieved the wakeup alarm.
+    alarm_reset();
+    #endif
+
     #if CIRCUITPY_NETWORK
     network_module_init();
     #endif
@@ -285,6 +289,7 @@ STATIC bool run_code_py(safe_mode_t safe_mode) {
         filesystem_flush();
         supervisor_allocation* heap = allocate_remaining_memory();
         start_mp(heap);
+
         found_main = maybe_run_list(supported_filenames, &result);
         #if CIRCUITPY_FULL_BUILD
         if (!found_main){
@@ -354,7 +359,6 @@ STATIC bool run_code_py(safe_mode_t safe_mode) {
             serial_write_compressed(translate("Woken up by alarm.\n"));
             board_init();
             supervisor_set_run_reason(RUN_REASON_STARTUP);
-            // TODO: Reset any volatile memory the user may have access to.
             return true;
         }
         #endif
diff --git a/ports/esp32s2/common-hal/alarm/time/TimeAlarm.c b/ports/esp32s2/common-hal/alarm/time/TimeAlarm.c
index d5e896c015..4d0bba2387 100644
--- a/ports/esp32s2/common-hal/alarm/time/TimeAlarm.c
+++ b/ports/esp32s2/common-hal/alarm/time/TimeAlarm.c
@@ -52,6 +52,7 @@ mp_obj_t alarm_time_timealarm_get_wakeup_alarm(size_t n_alarms, const mp_obj_t *
     alarm_time_time_alarm_obj_t *timer = m_new_obj(alarm_time_time_alarm_obj_t);
     timer->base.type = &alarm_time_time_alarm_type;
     // TODO: Set monotonic_time based on the RTC state.
+    timer->monotonic_time = 0.0f;
     return timer;
 }
 
diff --git a/shared-bindings/alarm/__init__.c b/shared-bindings/alarm/__init__.c
index 28e34ad6aa..5ef548ef27 100644
--- a/shared-bindings/alarm/__init__.c
+++ b/shared-bindings/alarm/__init__.c
@@ -197,7 +197,7 @@ STATIC mp_map_elem_t alarm_module_globals_table[] = {
 };
 STATIC MP_DEFINE_MUTABLE_DICT(alarm_module_globals, alarm_module_globals_table);
 
-void common_hal_alarm_set_wake_alarm(mp_obj_t alarm) {
+STATIC void alarm_set_wake_alarm(mp_obj_t alarm) {
     // Equivalent of:
     // alarm.wake_alarm = alarm
     mp_map_elem_t *elem =
@@ -207,6 +207,11 @@ void common_hal_alarm_set_wake_alarm(mp_obj_t alarm) {
     }
 }
 
+// Initialize .wake_alarm value.
+void alarm_save_wakeup_alarm(void) {
+    alarm_set_wake_alarm(common_hal_alarm_get_wake_alarm());
+}
+
 const mp_obj_module_t alarm_module = {
     .base = { &mp_type_module },
     .globals = (mp_obj_dict_t*)&alarm_module_globals,
diff --git a/shared-bindings/alarm/__init__.h b/shared-bindings/alarm/__init__.h
index 5a8c613d9d..8c4b6cad96 100644
--- a/shared-bindings/alarm/__init__.h
+++ b/shared-bindings/alarm/__init__.h
@@ -43,8 +43,11 @@ extern void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj
 // Deep sleep is entered outside of the VM so we omit the `common_hal_` prefix.
 extern NORETURN void alarm_enter_deep_sleep(void);
 
+extern mp_obj_t common_hal_alarm_get_wake_alarm(void);
+
 // Used by wake-up code.
-extern void common_hal_alarm_set_wake_alarm(mp_obj_t alarm);
+void alarm_save_wakeup_alarm(void);
+
 
 // True if an alarm is alerting. This is most useful for pretend deep sleep.
 extern bool alarm_woken_from_sleep(void);