feat(core): Add battery cycles updates into device telemetry.

diff --git a/core/embed/io/power_manager/stm32u5/power_manager.c b/core/embed/io/power_manager/stm32u5/power_manager.c
index 22417b7f8..782dc7692 100644
--- a/core/embed/io/power_manager/stm32u5/power_manager.c
+++ b/core/embed/io/power_manager/stm32u5/power_manager.c
@@ -32,6 +32,10 @@
 #include <sys/rtc_scheduler.h>
 #endif
 
+#ifdef USE_TELEMETRY
+#include <sec/telemetry.h>
+#endif
+
 #include "../battery/battery.h"
 #include "../power_manager_poll.h"
 #include "../stwlc38/stwlc38.h"
@@ -526,14 +530,11 @@ pm_status_t pm_store_data_to_backup_ram() {
     return PM_ERROR;
   }
 
-  /* Update battery cycle counter telemetry */
-  // float cycle_increment = bat_fetch_cycle_increment();
-  //
-  // Add cycle increment to telemetry
-  // #ifdef USE_TELEMETRY
-  //   telemetry_add_battery_cycle_increment(cycle_increment);
-  // #endif
-  //
+#ifdef USE_TELEMETRY
+  // Update battery cycle counter telemetry
+  float cycle_increment = bat_fetch_cycle_increment();
+  telemetry_update_battery_cycles(cycle_increment);
+#endif
 
   return PM_OK;
 }
diff --git a/core/embed/sec/telemetry/inc/sec/telemetry.h b/core/embed/sec/telemetry/inc/sec/telemetry.h
index 57d16b303..50cff2238 100644
--- a/core/embed/sec/telemetry/inc/sec/telemetry.h
+++ b/core/embed/sec/telemetry/inc/sec/telemetry.h
@@ -40,6 +40,7 @@ typedef struct {
   float min_temp_c; /**< Minimum recorded battery temperature in Celsius. */
   float max_temp_c; /**< Maximum recorded battery temperature in Celsius. */
   telemetry_batt_errors_t battery_errors; /**< Bitfield of battery errors. */
+  float battery_cycles; /**< Number of recorded battery cycles. */
 } telemetry_data_t;
 
 /**
@@ -63,6 +64,20 @@ void telemetry_update_battery_temp(float temp_c);
  */
 void telemetry_update_battery_errors(telemetry_batt_errors_t errors);
 
+/**
+ * @brief Increment battery cycles count in telemetry storage with an increment
+ *
+ * Battery cycles can only increase and should be updated with fractional
+ * increments accumulated over time from last call of this function.
+ *
+ * A battery cycle represents the cumulative current throughput equivalent to
+ * one complete charge-discharge cycle of a battery with capacity measured
+ * at 25°C.
+ *
+ * @param battery_cycles_inc battery cycles increment.
+ */
+void telemetry_update_battery_cycles(float battery_cycles_inc);
+
 /**
  * @brief Retrieve stored telemetry data.
  *
diff --git a/core/embed/sec/telemetry/telemetry.c b/core/embed/sec/telemetry/telemetry.c
index 9524877db..102ec702f 100644
--- a/core/embed/sec/telemetry/telemetry.c
+++ b/core/embed/sec/telemetry/telemetry.c
@@ -61,6 +61,7 @@ static void telemetry_init_record(void) {
   telemetry.data.min_temp_c = 500.0f;
   telemetry.data.max_temp_c = -500.0f;
   telemetry.data.battery_errors.all = 0;
+  telemetry.data.battery_cycles = 0.0f;
   telemetry_write(&telemetry);
 }
 
@@ -103,6 +104,20 @@ void telemetry_update_battery_errors(telemetry_batt_errors_t errors) {
   }
 }
 
+void telemetry_update_battery_cycles(float battery_cycles_inc) {
+  telemetry_t telemetry;
+  bool have = telemetry_read(&telemetry) && telemetry.initialized == 1;
+
+  if (!have) {
+    telemetry_init_record();
+  }
+
+  if (battery_cycles_inc > 0.0f) {
+    telemetry.data.battery_cycles += battery_cycles_inc;
+    telemetry_write(&telemetry);
+  }
+}
+
 bool telemetry_get(telemetry_data_t* out) {
   telemetry_t telemetry;
   if (!telemetry_read(&telemetry) || telemetry.initialized != 1) {
diff --git a/core/embed/sys/smcall/stm32/smcall_dispatch.c b/core/embed/sys/smcall/stm32/smcall_dispatch.c
index e5b43ba8e..21b1d7607 100644
--- a/core/embed/sys/smcall/stm32/smcall_dispatch.c
+++ b/core/embed/sys/smcall/stm32/smcall_dispatch.c
@@ -421,6 +421,16 @@ __attribute((no_stack_protector)) void smcall_handler(uint32_t *args,
       telemetry_update_battery_errors(errors);
     } break;
 
+    case SMCALL_TELEMETRY_UPDATE_BATT_CYCLES: {
+      union {
+        float f;
+        uint32_t u;
+      } u32_to_float = {.u = args[0]};
+
+      float battery_cycles_inc = u32_to_float.f;
+      telemetry_update_battery_cycles(battery_cycles_inc);
+    } break;
+
     case SMCALL_TELEMETRY_GET: {
       telemetry_data_t *out = (telemetry_data_t *)args[0];
       args[0] = telemetry_get__verified(out);
diff --git a/core/embed/sys/smcall/stm32/smcall_numbers.h b/core/embed/sys/smcall/stm32/smcall_numbers.h
index 74a432242..3f3005713 100644
--- a/core/embed/sys/smcall/stm32/smcall_numbers.h
+++ b/core/embed/sys/smcall/stm32/smcall_numbers.h
@@ -106,6 +106,7 @@ typedef enum {
 
   SMCALL_TELEMETRY_UPDATE_BATT_TEMP,
   SMCALL_TELEMETRY_UPDATE_BATT_ERRORS,
+  SMCALL_TELEMETRY_UPDATE_BATT_CYCLES,
   SMCALL_TELEMETRY_GET,
 
 } smcall_number_t;
diff --git a/core/embed/sys/smcall/stm32/smcall_stubs.c b/core/embed/sys/smcall/stm32/smcall_stubs.c
index d60b6c8e1..562f8f6c1 100644
--- a/core/embed/sys/smcall/stm32/smcall_stubs.c
+++ b/core/embed/sys/smcall/stm32/smcall_stubs.c
@@ -428,6 +428,15 @@ void telemetry_update_battery_errors(telemetry_batt_errors_t errors) {
   smcall_invoke1((uint32_t)errors.all, SMCALL_TELEMETRY_UPDATE_BATT_ERRORS);
 }
 
+void telemetry_update_battery_cycles(float battery_cycles_inc) {
+  union {
+    float f;
+    uint32_t u;
+  } float_to_u32 = {.f = battery_cycles_inc};
+
+  smcall_invoke1(float_to_u32.u, SMCALL_TELEMETRY_UPDATE_BATT_CYCLES);
+}
+
 bool telemetry_get(telemetry_data_t *out) {
   return (bool)smcall_invoke1((uint32_t)out, SMCALL_TELEMETRY_GET);
 }