From 59adb9033ce2bb5fbd29bd2c05fdb4475e882564 Mon Sep 17 00:00:00 2001
From: MSketcher <matt@bizfound.com>
Date: Thu, 21 May 2026 14:33:21 -0400
Subject: [PATCH 1/6] Proof of Concept

See if we can modify the behavior so the LEDs work
---
 examples/simple_repeater/main.cpp          | 50 ++++++++++++++++++++++
 variants/thinknode_m6/ThinkNodeM6Board.cpp | 22 ++++++++++
 variants/thinknode_m6/ThinkNodeM6Board.h   | 13 ++++--
 3 files changed, 82 insertions(+), 3 deletions(-)

diff --git a/examples/simple_repeater/main.cpp b/examples/simple_repeater/main.cpp
index 7fad801b98..918c26ca79 100644
--- a/examples/simple_repeater/main.cpp
+++ b/examples/simple_repeater/main.cpp
@@ -28,6 +28,19 @@ static unsigned long userBtnDownAt = 0;
 #define USER_BTN_HOLD_OFF_MILLIS 1500
 #endif
 
+#if defined(PIN_USER_BTN) && defined(THINKNODE_M6)
+static unsigned long m6BtnDownAt = 0;
+static bool m6BtnFeedbackArmed = false;
+// Visual thresholds during a long-press:
+//   <  3000 ms  : LEDs off (just sensing the press)
+//   3000-4000   : both LEDs blink in unison @ ~5 Hz
+//   4000-5000   : both LEDs solid on
+//   >= 5000 ms  : powerOff()
+#define M6_HOLD_BLINK_MS       3000
+#define M6_HOLD_SOLID_MS       4000
+#define M6_HOLD_POWEROFF_MS    5000
+#endif
+
 void setup() {
   Serial.begin(115200);
   delay(1000);
@@ -103,6 +116,10 @@ void setup() {
 #if ENABLE_ADVERT_ON_BOOT == 1
   the_mesh.sendSelfAdvertisement(16000, false);
 #endif
+
+#ifdef THINKNODE_M6
+  board.bootComplete();
+#endif
 }
 
 void loop() {
@@ -147,6 +164,39 @@ void loop() {
   }
 #endif
 
+#if defined(PIN_USER_BTN) && defined(THINKNODE_M6)
+  // Hold Function Button to power off the ThinkNode M6.
+  {
+    int btnState = digitalRead(PIN_USER_BTN);
+    if (btnState == LOW) {
+      if (m6BtnDownAt == 0) {
+        m6BtnDownAt = millis();
+        m6BtnFeedbackArmed = true;
+      }
+      unsigned long held = millis() - m6BtnDownAt;
+
+      if (held >= M6_HOLD_POWEROFF_MS) {
+        Serial.println("Powering off...");
+        board.powerOff();  // does not return
+      } else if (held >= M6_HOLD_SOLID_MS) {
+        digitalWrite(PIN_LED_RED,  HIGH);
+        digitalWrite(PIN_LED_BLUE, HIGH);
+      } else if (held >= M6_HOLD_BLINK_MS) {
+        bool on = ((held / 100) % 2) == 0;
+        digitalWrite(PIN_LED_RED,  on ? HIGH : LOW);
+        digitalWrite(PIN_LED_BLUE, on ? HIGH : LOW);
+      }
+    } else {
+      if (m6BtnFeedbackArmed && m6BtnDownAt != 0) {
+        digitalWrite(PIN_LED_RED,  LOW);
+        digitalWrite(PIN_LED_BLUE, LOW);
+      }
+      m6BtnDownAt = 0;
+      m6BtnFeedbackArmed = false;
+    }
+  }
+#endif
+
   the_mesh.loop();
   sensors.loop();
 #ifdef DISPLAY_CLASS
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.cpp b/variants/thinknode_m6/ThinkNodeM6Board.cpp
index 8ebae64c64..2b63df64c7 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.cpp
+++ b/variants/thinknode_m6/ThinkNodeM6Board.cpp
@@ -8,6 +8,20 @@
 void ThinkNodeM6Board::begin() {
   NRF52Board::begin();
 
+  // Soft-power latch: the Function Button momentarily applies VCC; firmware
+  // must drive PIN_PWR_EN HIGH within the first few hundred ms to keep the
+  // rail alive.
+  pinMode(PIN_PWR_EN, OUTPUT);
+  digitalWrite(PIN_PWR_EN, HIGH);
+
+  pinMode(PIN_LED_RED,  OUTPUT);
+  pinMode(PIN_LED_BLUE, OUTPUT);
+  digitalWrite(PIN_LED_RED,  HIGH);
+  digitalWrite(PIN_LED_BLUE, HIGH);
+  delay(1000);
+  digitalWrite(PIN_LED_RED,  LOW);
+  digitalWrite(PIN_LED_BLUE, LOW);
+
   Wire.begin();
 
 #ifdef P_LORA_TX_LED
@@ -15,6 +29,8 @@ void ThinkNodeM6Board::begin() {
   digitalWrite(P_LORA_TX_LED, LOW);
 #endif
 
+  pinMode(PIN_USER_BTN, INPUT_PULLUP);
+
   delay(10); // give sx1262 some time to power up
 }
 
@@ -33,4 +49,10 @@ uint16_t ThinkNodeM6Board::getBattMilliVolts() {
   // divider into account (providing the actual LIPO voltage)
   return (uint16_t)((float)adcvalue * REAL_VBAT_MV_PER_LSB);
 }
+
+void ThinkNodeM6Board::bootComplete() {
+  digitalWrite(PIN_LED_RED, HIGH); delay(150); digitalWrite(PIN_LED_RED, LOW);
+  delay(120);
+  digitalWrite(PIN_LED_BLUE, HIGH); delay(150); digitalWrite(PIN_LED_BLUE, LOW);
+}
 #endif
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.h b/variants/thinknode_m6/ThinkNodeM6Board.h
index 32baa2a0a2..9927e82c96 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.h
+++ b/variants/thinknode_m6/ThinkNodeM6Board.h
@@ -22,6 +22,7 @@ class ThinkNodeM6Board : public NRF52BoardDCDC {
   ThinkNodeM6Board() : NRF52Board("THINKNODE_M6_OTA") {}
   void begin();
   uint16_t getBattMilliVolts() override;
+  void bootComplete();
 
 #if defined(P_LORA_TX_LED)
   void onBeforeTransmit() override {
@@ -37,13 +38,19 @@ class ThinkNodeM6Board : public NRF52BoardDCDC {
   }
 
   void powerOff() override {
-
-    // turn off all leds, sd_power_system_off will not do this for us
+    // Turn off LEDs so the device visually confirms a clean shutdown.
+    digitalWrite(PIN_LED_RED,  LOW);
+    digitalWrite(PIN_LED_BLUE, LOW);
     #ifdef P_LORA_TX_LED
     digitalWrite(P_LORA_TX_LED, LOW);
     #endif
 
-    // power off board
+    // Break the soft-power latch — on battery, this physically cuts MCU power.
+    digitalWrite(PIN_PWR_EN, LOW);
+
+    // Belt-and-braces: if USB is providing power, the latch drop won't kill the chip.
     sd_power_system_off();
+
+    while (1) {}  // unreachable
   }
 };

From 2eb504e05e8acaaa246b6622dc783de2cd083714 Mon Sep 17 00:00:00 2001
From: MSketcher <matt@bizfound.com>
Date: Fri, 22 May 2026 08:02:19 -0400
Subject: [PATCH 2/6] LED behavior

---
 examples/simple_repeater/main.cpp             |  61 +++---
 variants/thinknode_m6/ThinkNodeM6Board.cpp    | 173 +++++++++++++++++-
 variants/thinknode_m6/ThinkNodeM6Board.h      |  21 +--
 variants/thinknode_m6/variant.cpp             |  32 ++++
 .../variant.cpp.tmp.12200.508f1cad751a        |  49 +++++
 5 files changed, 287 insertions(+), 49 deletions(-)
 create mode 100644 variants/thinknode_m6/variant.cpp.tmp.12200.508f1cad751a

diff --git a/examples/simple_repeater/main.cpp b/examples/simple_repeater/main.cpp
index 918c26ca79..76501b9935 100644
--- a/examples/simple_repeater/main.cpp
+++ b/examples/simple_repeater/main.cpp
@@ -30,22 +30,35 @@ static unsigned long userBtnDownAt = 0;
 
 #if defined(PIN_USER_BTN) && defined(THINKNODE_M6)
 static unsigned long m6BtnDownAt = 0;
-static bool m6BtnFeedbackArmed = false;
-// Visual thresholds during a long-press:
-//   <  3000 ms  : LEDs off (just sensing the press)
-//   3000-4000   : both LEDs blink in unison @ ~5 Hz
-//   4000-5000   : both LEDs solid on
-//   >= 5000 ms  : powerOff()
-#define M6_HOLD_BLINK_MS       3000
-#define M6_HOLD_SOLID_MS       4000
-#define M6_HOLD_POWEROFF_MS    5000
+// Long-press shutdown timeline (red LED only — no blue until the final flash):
+//   0-1000 ms     : LEDs off
+//   1000-1200 ms  : red flash @ 50% brightness
+//   1200-2000 ms  : red off
+//   2000-2200 ms  : red flash @ 50% brightness
+//   2200-3000 ms  : red off
+//   >= 3000 ms    : commitment — board.powerOff() shows red full bright for
+//                   1 s, then both LEDs flash 50 ms, then sleeps at the 4 s
+//                   mark regardless of whether the button is still held.
+#define M6_OFF_FLASH1_START_MS  1000
+#define M6_OFF_FLASH1_END_MS    1200
+#define M6_OFF_FLASH2_START_MS  2000
+#define M6_OFF_FLASH2_END_MS    2200
+#define M6_OFF_COMMIT_MS        3000
+#define M6_OFF_FLASH_BRIGHT     128   // ~50% of 255
 #endif
 
 void setup() {
   Serial.begin(115200);
-  delay(1000);
 
+#ifdef THINKNODE_M6
+  // The M6's board.begin() does a 0.5-second hold-to-power-on intent check.
+  // Run it before the pre-setup delay so the user's 0.5 s hold timer starts
+  // immediately on wake, not after a 1-second pre-delay.
+  board.begin();
+#else
+  delay(1000);
   board.begin();
+#endif
 
 #if defined(MESH_DEBUG) && defined(NRF52_PLATFORM)
   // give some extra time for serial to settle so
@@ -171,28 +184,30 @@ void loop() {
     if (btnState == LOW) {
       if (m6BtnDownAt == 0) {
         m6BtnDownAt = millis();
-        m6BtnFeedbackArmed = true;
       }
       unsigned long held = millis() - m6BtnDownAt;
 
-      if (held >= M6_HOLD_POWEROFF_MS) {
+      if (held >= M6_OFF_COMMIT_MS) {
+        // Commitment: powerOff() snaps red to full bright for 1 s, then sleeps.
         Serial.println("Powering off...");
         board.powerOff();  // does not return
-      } else if (held >= M6_HOLD_SOLID_MS) {
-        digitalWrite(PIN_LED_RED,  HIGH);
-        digitalWrite(PIN_LED_BLUE, HIGH);
-      } else if (held >= M6_HOLD_BLINK_MS) {
-        bool on = ((held / 100) % 2) == 0;
-        digitalWrite(PIN_LED_RED,  on ? HIGH : LOW);
-        digitalWrite(PIN_LED_BLUE, on ? HIGH : LOW);
+      } else if ((held >= M6_OFF_FLASH1_START_MS && held < M6_OFF_FLASH1_END_MS) ||
+                 (held >= M6_OFF_FLASH2_START_MS && held < M6_OFF_FLASH2_END_MS)) {
+        // Brief 50% red flash at the 2 s and 3 s marks.
+        analogWrite(PIN_LED_RED,  M6_OFF_FLASH_BRIGHT);
+        analogWrite(PIN_LED_BLUE, 0);
+      } else {
+        // All other pre-commit moments: LEDs off.
+        analogWrite(PIN_LED_RED,  0);
+        analogWrite(PIN_LED_BLUE, 0);
       }
     } else {
-      if (m6BtnFeedbackArmed && m6BtnDownAt != 0) {
-        digitalWrite(PIN_LED_RED,  LOW);
-        digitalWrite(PIN_LED_BLUE, LOW);
+      // Released before commitment — cancel and clear LEDs.
+      if (m6BtnDownAt != 0) {
+        analogWrite(PIN_LED_RED,  0);
+        analogWrite(PIN_LED_BLUE, 0);
       }
       m6BtnDownAt = 0;
-      m6BtnFeedbackArmed = false;
     }
   }
 #endif
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.cpp b/variants/thinknode_m6/ThinkNodeM6Board.cpp
index 2b63df64c7..18ce37d06e 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.cpp
+++ b/variants/thinknode_m6/ThinkNodeM6Board.cpp
@@ -5,23 +5,141 @@
 
 #include <Wire.h>
 
+// --- Boot-phase "disk activity" blue LED flicker ---
+// TIMER2 fires at pseudo-random intervals (10-100 ms); ISR toggles the blue
+// LED. Runs autonomously throughout setup() so the user gets continuous
+// "device is working" feedback during blocking calls like the_mesh.begin().
+// TIMER0 is reserved by SoftDevice; TIMER1 is often used by other libraries;
+// TIMER2 is reliably free in the M6 repeater build.
+static volatile bool s_flicker_blue_on = false;
+static uint32_t s_flicker_rng = 0xC0FFEE42;
+
+static inline uint32_t flicker_next_rand() {
+  // xorshift32 — cheap and good enough for "disk activity" jitter
+  uint32_t x = s_flicker_rng;
+  x ^= x << 13;
+  x ^= x >> 17;
+  x ^= x << 5;
+  s_flicker_rng = x;
+  return x;
+}
+
+extern "C" void TIMER2_IRQHandler(void) {
+  if (NRF_TIMER2->EVENTS_COMPARE[0]) {
+    NRF_TIMER2->EVENTS_COMPARE[0] = 0;
+    NRF_TIMER2->TASKS_CLEAR = 1;
+
+    s_flicker_blue_on = !s_flicker_blue_on;
+    nrf_gpio_pin_write(g_ADigitalPinMap[PIN_LED_BLUE], s_flicker_blue_on ? 1 : 0);
+
+    // Next toggle in 10-100 ms.
+    NRF_TIMER2->CC[0] = 10000 + (flicker_next_rand() % 90000);
+  }
+}
+
+static void startBootFlicker() {
+  NRF_TIMER2->TASKS_STOP = 1;
+  NRF_TIMER2->MODE = TIMER_MODE_MODE_Timer;
+  NRF_TIMER2->BITMODE = TIMER_BITMODE_BITMODE_32Bit << TIMER_BITMODE_BITMODE_Pos;
+  NRF_TIMER2->PRESCALER = 4;  // 16 MHz / 2^4 = 1 MHz tick (1 µs)
+  NRF_TIMER2->CC[0] = 30000;  // first toggle in ~30 ms
+  NRF_TIMER2->INTENSET = TIMER_INTENSET_COMPARE0_Msk;
+  NVIC_SetPriority(TIMER2_IRQn, 7);  // low priority — don't block radio/serial
+  NVIC_ClearPendingIRQ(TIMER2_IRQn);
+  NVIC_EnableIRQ(TIMER2_IRQn);
+  NRF_TIMER2->TASKS_CLEAR = 1;
+  NRF_TIMER2->TASKS_START = 1;
+}
+
+static void stopBootFlicker() {
+  NRF_TIMER2->TASKS_STOP = 1;
+  NRF_TIMER2->INTENCLR = TIMER_INTENCLR_COMPARE0_Msk;
+  NVIC_DisableIRQ(TIMER2_IRQn);
+  NVIC_ClearPendingIRQ(TIMER2_IRQn);
+  digitalWrite(PIN_LED_BLUE, LOW);
+  s_flicker_blue_on = false;
+}
+
+// Arm the Function Button as a SENSE-LOW wake source and enter SYSTEMOFF.
+// SoftDevice may not be enabled in non-BLE builds (repeater), so we fall back
+// to a direct register write — mirrors NRF52Board::enterSystemOff().
+static void enterDeepSleep() {
+  nrf_gpio_cfg_sense_input(digitalPinToInterrupt(g_ADigitalPinMap[PIN_USER_BTN]),
+                           NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);
+
+  uint8_t sd_enabled = 0;
+  sd_softdevice_is_enabled(&sd_enabled);
+  if (sd_enabled) {
+    if (sd_power_system_off() == NRF_ERROR_SOFTDEVICE_NOT_ENABLED) {
+      sd_enabled = 0;
+    }
+  }
+  if (!sd_enabled) {
+    NRF_POWER->SYSTEMOFF = POWER_SYSTEMOFF_SYSTEMOFF_Enter;
+  }
+  NVIC_SystemReset();  // unreachable in normal flow
+}
+
+// Captured by an early constructor in variant.cpp before SystemInit()'s
+// errata-136 workaround scrubs the RESETPIN bit. g_m6_was_powered is the
+// GPREGRET2-based "did firmware run in this power session?" flag — false
+// means power was completely lost (e.g., battery died, solar recharge),
+// which we treat as a recovery boot.
+extern volatile uint32_t g_m6_reset_reason;
+extern volatile bool     g_m6_was_powered;
+
 void ThinkNodeM6Board::begin() {
   NRF52Board::begin();
 
-  // Soft-power latch: the Function Button momentarily applies VCC; firmware
-  // must drive PIN_PWR_EN HIGH within the first few hundred ms to keep the
-  // rail alive.
-  pinMode(PIN_PWR_EN, OUTPUT);
-  digitalWrite(PIN_PWR_EN, HIGH);
+  // PIN_PWR_EN (peripheral power rail) is already driven HIGH by
+  // initVariant() in variant.cpp; no need to re-assert it here.
 
+  // NOTE: do not call analogWrite() here. On the Adafruit nRF52 core,
+  // analogWrite() routes the pin to the PWM peripheral and subsequent
+  // digitalWrite() calls no longer drive the pin. initVariant() already left
+  // both LEDs LOW via digitalWrite, so we can use digitalWrite the whole way
+  // through the boot sequence. powerOff() uses analogWrite later, after the
+  // boot LEDs are no longer needed.
+  pinMode(PIN_USER_BTN, INPUT_PULLUP);
   pinMode(PIN_LED_RED,  OUTPUT);
   pinMode(PIN_LED_BLUE, OUTPUT);
+  digitalWrite(PIN_LED_RED,  LOW);
+  digitalWrite(PIN_LED_BLUE, LOW);
+  delay(20);  // pin settle / debounce
+
+  // Decide whether to actually boot based on three signals:
+  //   - RESETPIN bit set → user pressed reset → boot
+  //   - OFF bit set → SENSE-LOW wake (only configured on PIN_USER_BTN) →
+  //     user pressed the Function Button → boot
+  //   - !g_m6_was_powered → GPREGRET2 magic was cleared by full power loss,
+  //     so this is a recovery from a dead battery / solar recharge → boot
+  //     automatically (important for unattended deployments)
+  // Otherwise (POR/brownout/USB transient while we were already running) →
+  // re-sleep silently.
+  bool from_reset_pin   = (g_m6_reset_reason & POWER_RESETREAS_RESETPIN_Msk) != 0;
+  bool from_button_wake = (g_m6_reset_reason & POWER_RESETREAS_OFF_Msk)      != 0;
+  bool from_power_loss  = !g_m6_was_powered;
+
+  if (!from_reset_pin && !from_button_wake && !from_power_loss) {
+    // No deliberate user action and we were already powered — re-sleep.
+    enterDeepSleep();
+  }
+
+  // Intent confirmed — both LEDs full bright for 1 second.
   digitalWrite(PIN_LED_RED,  HIGH);
   digitalWrite(PIN_LED_BLUE, HIGH);
   delay(1000);
   digitalWrite(PIN_LED_RED,  LOW);
   digitalWrite(PIN_LED_BLUE, LOW);
 
+  // 1-second gap (LEDs off), then start the boot-phase indicator: red solid
+  // on, blue flickering like a disk-drive activity LED. The flicker runs on
+  // a TIMER2 interrupt so it keeps going through every blocking call in
+  // setup() (the_mesh.begin() etc.). It's stopped by bootComplete() at the end.
+  delay(1000);
+  digitalWrite(PIN_LED_RED, HIGH);
+  startBootFlicker();
+
   Wire.begin();
 
 #ifdef P_LORA_TX_LED
@@ -29,11 +147,38 @@ void ThinkNodeM6Board::begin() {
   digitalWrite(P_LORA_TX_LED, LOW);
 #endif
 
-  pinMode(PIN_USER_BTN, INPUT_PULLUP);
-
   delay(10); // give sx1262 some time to power up
 }
 
+void ThinkNodeM6Board::powerOff() {
+#ifdef P_LORA_TX_LED
+  digitalWrite(P_LORA_TX_LED, LOW);
+#endif
+
+  // Shutdown cue: red full bright for 1 s.
+  analogWrite(PIN_LED_BLUE, 0);
+  analogWrite(PIN_LED_RED,  255);
+  delay(1000);
+  analogWrite(PIN_LED_RED, 0);
+
+  // Final "goodbye": brief both-LED flash so the user knows we're committed
+  // and the device is going dark right now.
+  analogWrite(PIN_LED_RED,  255);
+  analogWrite(PIN_LED_BLUE, 255);
+  delay(50);
+  analogWrite(PIN_LED_RED,  0);
+  analogWrite(PIN_LED_BLUE, 0);
+
+  // If the button is still held, we can't yet enter SYSTEMOFF (SENSE-LOW
+  // would wake us immediately). Wait silently for release — no LEDs lit,
+  // so the wait is invisible.
+  while (digitalRead(PIN_USER_BTN) == LOW) delay(10);
+
+  Serial.flush();
+  delay(50);
+  enterDeepSleep();
+}
+
 uint16_t ThinkNodeM6Board::getBattMilliVolts() {
   int adcvalue = 0;
 
@@ -51,8 +196,16 @@ uint16_t ThinkNodeM6Board::getBattMilliVolts() {
 }
 
 void ThinkNodeM6Board::bootComplete() {
-  digitalWrite(PIN_LED_RED, HIGH); delay(150); digitalWrite(PIN_LED_RED, LOW);
-  delay(120);
-  digitalWrite(PIN_LED_BLUE, HIGH); delay(150); digitalWrite(PIN_LED_BLUE, LOW);
+  // Stop the flicker timer, turn red off, pause 1 second (everything dark)
+  // to clearly delimit the boot phase, then flash blue for 100 ms as the
+  // "device is up" signal.
+  stopBootFlicker();
+  digitalWrite(PIN_LED_RED,  LOW);
+  digitalWrite(PIN_LED_BLUE, LOW);
+  delay(1000);
+  digitalWrite(PIN_LED_BLUE, HIGH);
+  delay(100);
+  digitalWrite(PIN_LED_BLUE, LOW);
 }
+
 #endif
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.h b/variants/thinknode_m6/ThinkNodeM6Board.h
index 9927e82c96..26b2d89e20 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.h
+++ b/variants/thinknode_m6/ThinkNodeM6Board.h
@@ -22,6 +22,10 @@ class ThinkNodeM6Board : public NRF52BoardDCDC {
   ThinkNodeM6Board() : NRF52Board("THINKNODE_M6_OTA") {}
   void begin();
   uint16_t getBattMilliVolts() override;
+
+  // Called at the very end of setup() to mark "boot complete": stops the
+  // disk-activity-style blue flicker started in begin(), turns the red LED
+  // off, and flashes the blue LED for 100 ms.
   void bootComplete();
 
 #if defined(P_LORA_TX_LED)
@@ -37,20 +41,5 @@ class ThinkNodeM6Board : public NRF52BoardDCDC {
     return "Elecrow ThinkNode M6";
   }
 
-  void powerOff() override {
-    // Turn off LEDs so the device visually confirms a clean shutdown.
-    digitalWrite(PIN_LED_RED,  LOW);
-    digitalWrite(PIN_LED_BLUE, LOW);
-    #ifdef P_LORA_TX_LED
-    digitalWrite(P_LORA_TX_LED, LOW);
-    #endif
-
-    // Break the soft-power latch — on battery, this physically cuts MCU power.
-    digitalWrite(PIN_PWR_EN, LOW);
-
-    // Belt-and-braces: if USB is providing power, the latch drop won't kill the chip.
-    sd_power_system_off();
-
-    while (1) {}  // unreachable
-  }
+  void powerOff() override;
 };
diff --git a/variants/thinknode_m6/variant.cpp b/variants/thinknode_m6/variant.cpp
index c88f387db6..4c1ac98262 100644
--- a/variants/thinknode_m6/variant.cpp
+++ b/variants/thinknode_m6/variant.cpp
@@ -1,6 +1,38 @@
 #include "variant.h"
 #include "wiring_constants.h"
 #include "wiring_digital.h"
+#include "nrf.h"
+
+// Capture NRF_POWER->RESETREAS before SystemInit() runs the Nordic errata-136
+// workaround that clears the RESETPIN bit. Priority 101 places this before
+// SystemInit (102) and all C++ static constructors. Exposed via the globals
+// below so ThinkNodeM6Board::begin() can decide whether to boot or re-sleep.
+//
+// We also leverage GPREGRET2 (an 8-bit retained register) to detect full
+// power loss: the register persists through SYSTEMOFF but is cleared when
+// the chip loses power completely. By stamping a magic value on every boot,
+// the next boot can tell "we cleanly went to SYSTEMOFF" (magic still there)
+// from "battery died and just came back" (magic cleared). The latter case
+// boots automatically — important for unattended solar-powered deployments.
+//
+// NOTE: GPREGRET2 is also written by NRF52Board::enterSystemOff() when
+// NRF52_POWER_MANAGEMENT is defined. That build flag is NOT set for any M6
+// env today, so there is no conflict. If it's ever enabled for the M6, the
+// magic value here will collide with the shutdown-reason byte stored there.
+#define M6_GPREGRET2_MAGIC      0xA5
+volatile uint32_t g_m6_reset_reason  = 0;
+volatile bool     g_m6_was_powered   = false;
+
+extern "C" __attribute__((constructor(101))) void m6_capture_resetreas(void) {
+  g_m6_reset_reason = NRF_POWER->RESETREAS;
+  // Clear sticky bits so the next boot sees a fresh state.
+  NRF_POWER->RESETREAS = 0xFFFFFFFFul;
+
+  // GPREGRET2 magic value: present = firmware ran in this power session
+  // (we cleanly went to SYSTEMOFF and came back); absent = power was lost.
+  g_m6_was_powered = (NRF_POWER->GPREGRET2 == M6_GPREGRET2_MAGIC);
+  NRF_POWER->GPREGRET2 = M6_GPREGRET2_MAGIC;  // stamp it for next boot
+}
 
 const uint32_t g_ADigitalPinMap[] = {
   0xff, 0xff, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
diff --git a/variants/thinknode_m6/variant.cpp.tmp.12200.508f1cad751a b/variants/thinknode_m6/variant.cpp.tmp.12200.508f1cad751a
new file mode 100644
index 0000000000..278aae6e43
--- /dev/null
+++ b/variants/thinknode_m6/variant.cpp.tmp.12200.508f1cad751a
@@ -0,0 +1,49 @@
+#include "variant.h"
+#include "wiring_constants.h"
+#include "wiring_digital.h"
+#include "nrf.h"
+
+// Capture NRF_POWER->RESETREAS before SystemInit() runs the Nordic errata-136
+// workaround that clears the RESETPIN bit. Priority 101 places this before
+// SystemInit (102) and all C++ static constructors. Exposed via the global
+// g_m6_reset_reason so ThinkNodeM6Board::begin() can decide whether to honor
+// the intent-check (button hold) or bypass it (reset-pin reboot).
+volatile uint32_t g_m6_reset_reason = 0;
+
+extern "C" __attribute__((constructor(101))) void m6_capture_resetreas(void) {
+  g_m6_reset_reason = NRF_POWER->RESETREAS;
+  // Clear sticky bits so the next boot sees a fresh state.
+  NRF_POWER->RESETREAS = 0xFFFFFFFFul;
+}
+
+const uint32_t g_ADigitalPinMap[] = {
+  0xff, 0xff, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
+  14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
+  27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
+  40, 41, 42, 43, 44, 45, 46, 47
+};
+
+void initVariant() {
+  pinMode(PIN_PWR_EN, OUTPUT);
+  digitalWrite(PIN_PWR_EN, HIGH);
+
+  pinMode(QSPI_FLASH_EN, OUTPUT);
+  digitalWrite(QSPI_FLASH_EN, HIGH);
+
+  // For now stick adc_ctrl to fixed value
+  pinMode(PIN_ADC_CTRL, OUTPUT);
+  digitalWrite(PIN_ADC_CTRL, LOW);
+
+  pinMode(PIN_LED_RED, OUTPUT);
+  pinMode(PIN_LED_BLUE, OUTPUT);
+  digitalWrite(PIN_LED_BLUE, LOW);
+  digitalWrite(PIN_LED_RED, LOW);
+
+  // gps
+  pinMode(PIN_GPS_STANDBY, OUTPUT);
+  digitalWrite(PIN_GPS_STANDBY, HIGH);
+  pinMode(PIN_GPS_EN, OUTPUT);
+  digitalWrite(PIN_GPS_EN, HIGH);
+  pinMode(PIN_GPS_RESET, OUTPUT);
+  digitalWrite(PIN_GPS_RESET, HIGH);
+}

From 913299e826ef9aa863897a91a2ef048c8da6bca8 Mon Sep 17 00:00:00 2001
From: MSketcher <matt@bizfound.com>
Date: Fri, 22 May 2026 08:49:19 -0400
Subject: [PATCH 3/6] Final cleanup

---
 examples/simple_repeater/main.cpp             | 67 ++++++++++++-------
 variants/thinknode_m6/ThinkNodeM6Board.cpp    |  2 +-
 .../variant.cpp.tmp.12200.508f1cad751a        | 49 --------------
 3 files changed, 45 insertions(+), 73 deletions(-)
 delete mode 100644 variants/thinknode_m6/variant.cpp.tmp.12200.508f1cad751a

diff --git a/examples/simple_repeater/main.cpp b/examples/simple_repeater/main.cpp
index 76501b9935..44e357c797 100644
--- a/examples/simple_repeater/main.cpp
+++ b/examples/simple_repeater/main.cpp
@@ -31,29 +31,36 @@ static unsigned long userBtnDownAt = 0;
 #if defined(PIN_USER_BTN) && defined(THINKNODE_M6)
 static unsigned long m6BtnDownAt = 0;
 // Long-press shutdown timeline (red LED only — no blue until the final flash):
-//   0-1000 ms     : LEDs off
-//   1000-1200 ms  : red flash @ 50% brightness
+//   0-200 ms      : red flash @ 50% — immediate ack of the press
+//   200-1000 ms   : red off
+//   1000-1200 ms  : red flash @ 50%
 //   1200-2000 ms  : red off
-//   2000-2200 ms  : red flash @ 50% brightness
-//   2200-3000 ms  : red off
-//   >= 3000 ms    : commitment — board.powerOff() shows red full bright for
-//                   1 s, then both LEDs flash 50 ms, then sleeps at the 4 s
-//                   mark regardless of whether the button is still held.
-#define M6_OFF_FLASH1_START_MS  1000
-#define M6_OFF_FLASH1_END_MS    1200
-#define M6_OFF_FLASH2_START_MS  2000
-#define M6_OFF_FLASH2_END_MS    2200
-#define M6_OFF_COMMIT_MS        3000
+//   >= 2000 ms    : commitment — board.powerOff() shows red full bright for
+//                   1 s (the third "blink"), then both LEDs flash 50 ms,
+//                   then sleeps at the 3 s mark regardless of button state.
+#define M6_OFF_FLASH1_START_MS  0
+#define M6_OFF_FLASH1_END_MS    200
+#define M6_OFF_FLASH2_START_MS  1000
+#define M6_OFF_FLASH2_END_MS    1200
+#define M6_OFF_COMMIT_MS        2000
 #define M6_OFF_FLASH_BRIGHT     128   // ~50% of 255
+
+// Tap (quick press+release) sends an advertisement and blinks Morse "A" on
+// the blue LED to acknowledge.
+#define M6_TAP_MIN_MS           30    // debounce floor
+#define M6_TAP_MAX_MS           500   // anything longer is a hold attempt
+#define M6_MORSE_DOT_MS         200
+#define M6_MORSE_GAP_MS         200
+#define M6_MORSE_DASH_MS        600
 #endif
 
 void setup() {
   Serial.begin(115200);
 
 #ifdef THINKNODE_M6
-  // The M6's board.begin() does a 0.5-second hold-to-power-on intent check.
-  // Run it before the pre-setup delay so the user's 0.5 s hold timer starts
-  // immediately on wake, not after a 1-second pre-delay.
+  // The M6's board.begin() drives the boot LED sequence. Run it before the
+  // pre-setup delay so the LEDs come on as soon as the chip wakes, rather
+  // than after a 1-second silent gap.
   board.begin();
 #else
   delay(1000);
@@ -193,19 +200,33 @@ void loop() {
         board.powerOff();  // does not return
       } else if ((held >= M6_OFF_FLASH1_START_MS && held < M6_OFF_FLASH1_END_MS) ||
                  (held >= M6_OFF_FLASH2_START_MS && held < M6_OFF_FLASH2_END_MS)) {
-        // Brief 50% red flash at the 2 s and 3 s marks.
-        analogWrite(PIN_LED_RED,  M6_OFF_FLASH_BRIGHT);
-        analogWrite(PIN_LED_BLUE, 0);
+        // Brief 50% red flash at the 0 s (immediate ack) and 1 s marks.
+        analogWrite(PIN_LED_RED,    M6_OFF_FLASH_BRIGHT);
+        digitalWrite(PIN_LED_BLUE,  LOW);
       } else {
         // All other pre-commit moments: LEDs off.
-        analogWrite(PIN_LED_RED,  0);
-        analogWrite(PIN_LED_BLUE, 0);
+        analogWrite(PIN_LED_RED,    0);
+        digitalWrite(PIN_LED_BLUE,  LOW);
       }
     } else {
-      // Released before commitment — cancel and clear LEDs.
+      // Button released. Could be a cancel (started off-sequence but let go)
+      // or a tap (quick press+release to send an advert).
       if (m6BtnDownAt != 0) {
-        analogWrite(PIN_LED_RED,  0);
-        analogWrite(PIN_LED_BLUE, 0);
+        unsigned long held = millis() - m6BtnDownAt;
+        analogWrite(PIN_LED_RED,    0);
+        digitalWrite(PIN_LED_BLUE,  LOW);
+
+        if (held >= M6_TAP_MIN_MS && held < M6_TAP_MAX_MS) {
+          // Tap — broadcast an advert and blink Morse "A" (dot-dash) on
+          // the blue LED. digitalWrite (not analogWrite) so the blue pin
+          // stays in pure GPIO mode and the LoRa TX LED keeps working.
+          Serial.println("Tap -> sending advert");
+          the_mesh.sendSelfAdvertisement(16000, false);
+          digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DOT_MS);
+          digitalWrite(PIN_LED_BLUE, LOW);  delay(M6_MORSE_GAP_MS);
+          digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DASH_MS);
+          digitalWrite(PIN_LED_BLUE, LOW);
+        }
       }
       m6BtnDownAt = 0;
     }
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.cpp b/variants/thinknode_m6/ThinkNodeM6Board.cpp
index 18ce37d06e..3c9a3d7edb 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.cpp
+++ b/variants/thinknode_m6/ThinkNodeM6Board.cpp
@@ -125,7 +125,7 @@ void ThinkNodeM6Board::begin() {
     enterDeepSleep();
   }
 
-  // Intent confirmed — both LEDs full bright for 1 second.
+  // Boot indicator: both LEDs full bright for 1 second.
   digitalWrite(PIN_LED_RED,  HIGH);
   digitalWrite(PIN_LED_BLUE, HIGH);
   delay(1000);
diff --git a/variants/thinknode_m6/variant.cpp.tmp.12200.508f1cad751a b/variants/thinknode_m6/variant.cpp.tmp.12200.508f1cad751a
deleted file mode 100644
index 278aae6e43..0000000000
--- a/variants/thinknode_m6/variant.cpp.tmp.12200.508f1cad751a
+++ /dev/null
@@ -1,49 +0,0 @@
-#include "variant.h"
-#include "wiring_constants.h"
-#include "wiring_digital.h"
-#include "nrf.h"
-
-// Capture NRF_POWER->RESETREAS before SystemInit() runs the Nordic errata-136
-// workaround that clears the RESETPIN bit. Priority 101 places this before
-// SystemInit (102) and all C++ static constructors. Exposed via the global
-// g_m6_reset_reason so ThinkNodeM6Board::begin() can decide whether to honor
-// the intent-check (button hold) or bypass it (reset-pin reboot).
-volatile uint32_t g_m6_reset_reason = 0;
-
-extern "C" __attribute__((constructor(101))) void m6_capture_resetreas(void) {
-  g_m6_reset_reason = NRF_POWER->RESETREAS;
-  // Clear sticky bits so the next boot sees a fresh state.
-  NRF_POWER->RESETREAS = 0xFFFFFFFFul;
-}
-
-const uint32_t g_ADigitalPinMap[] = {
-  0xff, 0xff, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
-  14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
-  27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
-  40, 41, 42, 43, 44, 45, 46, 47
-};
-
-void initVariant() {
-  pinMode(PIN_PWR_EN, OUTPUT);
-  digitalWrite(PIN_PWR_EN, HIGH);
-
-  pinMode(QSPI_FLASH_EN, OUTPUT);
-  digitalWrite(QSPI_FLASH_EN, HIGH);
-
-  // For now stick adc_ctrl to fixed value
-  pinMode(PIN_ADC_CTRL, OUTPUT);
-  digitalWrite(PIN_ADC_CTRL, LOW);
-
-  pinMode(PIN_LED_RED, OUTPUT);
-  pinMode(PIN_LED_BLUE, OUTPUT);
-  digitalWrite(PIN_LED_BLUE, LOW);
-  digitalWrite(PIN_LED_RED, LOW);
-
-  // gps
-  pinMode(PIN_GPS_STANDBY, OUTPUT);
-  digitalWrite(PIN_GPS_STANDBY, HIGH);
-  pinMode(PIN_GPS_EN, OUTPUT);
-  digitalWrite(PIN_GPS_EN, HIGH);
-  pinMode(PIN_GPS_RESET, OUTPUT);
-  digitalWrite(PIN_GPS_RESET, HIGH);
-}

From d5a9845b0aa036211805073ea38e7efe18d00f84 Mon Sep 17 00:00:00 2001
From: AtlavoxDev <matt@bizfound.com>
Date: Fri, 22 May 2026 09:48:14 -0400
Subject: [PATCH 4/6] Comment cleanup

---
 examples/simple_repeater/main.cpp          | 30 +++----
 variants/thinknode_m6/ThinkNodeM6Board.cpp | 91 +++++++++-------------
 variants/thinknode_m6/ThinkNodeM6Board.h   |  5 +-
 variants/thinknode_m6/variant.cpp          | 38 ++++-----
 4 files changed, 62 insertions(+), 102 deletions(-)

diff --git a/examples/simple_repeater/main.cpp b/examples/simple_repeater/main.cpp
index 44e357c797..00f2624b03 100644
--- a/examples/simple_repeater/main.cpp
+++ b/examples/simple_repeater/main.cpp
@@ -30,14 +30,8 @@ static unsigned long userBtnDownAt = 0;
 
 #if defined(PIN_USER_BTN) && defined(THINKNODE_M6)
 static unsigned long m6BtnDownAt = 0;
-// Long-press shutdown timeline (red LED only — no blue until the final flash):
-//   0-200 ms      : red flash @ 50% — immediate ack of the press
-//   200-1000 ms   : red off
-//   1000-1200 ms  : red flash @ 50%
-//   1200-2000 ms  : red off
-//   >= 2000 ms    : commitment — board.powerOff() shows red full bright for
-//                   1 s (the third "blink"), then both LEDs flash 50 ms,
-//                   then sleeps at the 3 s mark regardless of button state.
+// Long-press shutdown: red LED flashes briefly at 0 s and 1 s during the
+// hold, then board.powerOff() runs the final shutdown cue at 2 s.
 #define M6_OFF_FLASH1_START_MS  0
 #define M6_OFF_FLASH1_END_MS    200
 #define M6_OFF_FLASH2_START_MS  1000
@@ -45,8 +39,7 @@ static unsigned long m6BtnDownAt = 0;
 #define M6_OFF_COMMIT_MS        2000
 #define M6_OFF_FLASH_BRIGHT     128   // ~50% of 255
 
-// Tap (quick press+release) sends an advertisement and blinks Morse "A" on
-// the blue LED to acknowledge.
+// Quick tap (press+release) sends an advert; blue LED blinks Morse "A".
 #define M6_TAP_MIN_MS           30    // debounce floor
 #define M6_TAP_MAX_MS           500   // anything longer is a hold attempt
 #define M6_MORSE_DOT_MS         200
@@ -58,9 +51,8 @@ void setup() {
   Serial.begin(115200);
 
 #ifdef THINKNODE_M6
-  // The M6's board.begin() drives the boot LED sequence. Run it before the
-  // pre-setup delay so the LEDs come on as soon as the chip wakes, rather
-  // than after a 1-second silent gap.
+  // M6's board.begin() drives the boot LED sequence; run it before any
+  // pre-setup delays so the LEDs come on immediately at wake.
   board.begin();
 #else
   delay(1000);
@@ -195,31 +187,27 @@ void loop() {
       unsigned long held = millis() - m6BtnDownAt;
 
       if (held >= M6_OFF_COMMIT_MS) {
-        // Commitment: powerOff() snaps red to full bright for 1 s, then sleeps.
         Serial.println("Powering off...");
         board.powerOff();  // does not return
       } else if ((held >= M6_OFF_FLASH1_START_MS && held < M6_OFF_FLASH1_END_MS) ||
                  (held >= M6_OFF_FLASH2_START_MS && held < M6_OFF_FLASH2_END_MS)) {
-        // Brief 50% red flash at the 0 s (immediate ack) and 1 s marks.
         analogWrite(PIN_LED_RED,    M6_OFF_FLASH_BRIGHT);
         digitalWrite(PIN_LED_BLUE,  LOW);
       } else {
-        // All other pre-commit moments: LEDs off.
         analogWrite(PIN_LED_RED,    0);
         digitalWrite(PIN_LED_BLUE,  LOW);
       }
     } else {
-      // Button released. Could be a cancel (started off-sequence but let go)
-      // or a tap (quick press+release to send an advert).
+      // Button released. Quick press+release = tap (send advert). Longer
+      // holds that don't reach the commit threshold are silent cancels.
       if (m6BtnDownAt != 0) {
         unsigned long held = millis() - m6BtnDownAt;
         analogWrite(PIN_LED_RED,    0);
         digitalWrite(PIN_LED_BLUE,  LOW);
 
         if (held >= M6_TAP_MIN_MS && held < M6_TAP_MAX_MS) {
-          // Tap — broadcast an advert and blink Morse "A" (dot-dash) on
-          // the blue LED. digitalWrite (not analogWrite) so the blue pin
-          // stays in pure GPIO mode and the LoRa TX LED keeps working.
+          // Tap → advert + Morse "A" on blue. digitalWrite keeps blue in
+          // pure GPIO mode so the LoRa TX LED indicator still works.
           Serial.println("Tap -> sending advert");
           the_mesh.sendSelfAdvertisement(16000, false);
           digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DOT_MS);
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.cpp b/variants/thinknode_m6/ThinkNodeM6Board.cpp
index 3c9a3d7edb..d42efdecdb 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.cpp
+++ b/variants/thinknode_m6/ThinkNodeM6Board.cpp
@@ -5,17 +5,14 @@
 
 #include <Wire.h>
 
-// --- Boot-phase "disk activity" blue LED flicker ---
-// TIMER2 fires at pseudo-random intervals (10-100 ms); ISR toggles the blue
-// LED. Runs autonomously throughout setup() so the user gets continuous
-// "device is working" feedback during blocking calls like the_mesh.begin().
-// TIMER0 is reserved by SoftDevice; TIMER1 is often used by other libraries;
-// TIMER2 is reliably free in the M6 repeater build.
+// Boot-phase blue LED flicker. TIMER2 fires at pseudo-random 10-100 ms
+// intervals; the ISR toggles the blue LED. Runs in the background through
+// every blocking call in setup() (mesh init, etc.).
 static volatile bool s_flicker_blue_on = false;
 static uint32_t s_flicker_rng = 0xC0FFEE42;
 
+// xorshift32 PRNG for flicker jitter.
 static inline uint32_t flicker_next_rand() {
-  // xorshift32 — cheap and good enough for "disk activity" jitter
   uint32_t x = s_flicker_rng;
   x ^= x << 13;
   x ^= x >> 17;
@@ -32,8 +29,7 @@ extern "C" void TIMER2_IRQHandler(void) {
     s_flicker_blue_on = !s_flicker_blue_on;
     nrf_gpio_pin_write(g_ADigitalPinMap[PIN_LED_BLUE], s_flicker_blue_on ? 1 : 0);
 
-    // Next toggle in 10-100 ms.
-    NRF_TIMER2->CC[0] = 10000 + (flicker_next_rand() % 90000);
+    NRF_TIMER2->CC[0] = 10000 + (flicker_next_rand() % 90000);  // 10-100 ms
   }
 }
 
@@ -44,7 +40,7 @@ static void startBootFlicker() {
   NRF_TIMER2->PRESCALER = 4;  // 16 MHz / 2^4 = 1 MHz tick (1 µs)
   NRF_TIMER2->CC[0] = 30000;  // first toggle in ~30 ms
   NRF_TIMER2->INTENSET = TIMER_INTENSET_COMPARE0_Msk;
-  NVIC_SetPriority(TIMER2_IRQn, 7);  // low priority — don't block radio/serial
+  NVIC_SetPriority(TIMER2_IRQn, 7);  // low priority
   NVIC_ClearPendingIRQ(TIMER2_IRQn);
   NVIC_EnableIRQ(TIMER2_IRQn);
   NRF_TIMER2->TASKS_CLEAR = 1;
@@ -61,8 +57,8 @@ static void stopBootFlicker() {
 }
 
 // Arm the Function Button as a SENSE-LOW wake source and enter SYSTEMOFF.
-// SoftDevice may not be enabled in non-BLE builds (repeater), so we fall back
-// to a direct register write — mirrors NRF52Board::enterSystemOff().
+// Falls back to a direct register write if SoftDevice isn't enabled
+// (non-BLE builds).
 static void enterDeepSleep() {
   nrf_gpio_cfg_sense_input(digitalPinToInterrupt(g_ADigitalPinMap[PIN_USER_BTN]),
                            NRF_GPIO_PIN_PULLUP, NRF_GPIO_PIN_SENSE_LOW);
@@ -77,29 +73,20 @@ static void enterDeepSleep() {
   if (!sd_enabled) {
     NRF_POWER->SYSTEMOFF = POWER_SYSTEMOFF_SYSTEMOFF_Enter;
   }
-  NVIC_SystemReset();  // unreachable in normal flow
+  NVIC_SystemReset();  // unreachable
 }
 
-// Captured by an early constructor in variant.cpp before SystemInit()'s
-// errata-136 workaround scrubs the RESETPIN bit. g_m6_was_powered is the
-// GPREGRET2-based "did firmware run in this power session?" flag — false
-// means power was completely lost (e.g., battery died, solar recharge),
-// which we treat as a recovery boot.
+// Captured by variant.cpp's early constructor. See that file for details.
 extern volatile uint32_t g_m6_reset_reason;
-extern volatile bool     g_m6_was_powered;
+extern volatile bool     g_m6_was_shutdown;
 
 void ThinkNodeM6Board::begin() {
   NRF52Board::begin();
 
-  // PIN_PWR_EN (peripheral power rail) is already driven HIGH by
-  // initVariant() in variant.cpp; no need to re-assert it here.
-
-  // NOTE: do not call analogWrite() here. On the Adafruit nRF52 core,
-  // analogWrite() routes the pin to the PWM peripheral and subsequent
-  // digitalWrite() calls no longer drive the pin. initVariant() already left
-  // both LEDs LOW via digitalWrite, so we can use digitalWrite the whole way
-  // through the boot sequence. powerOff() uses analogWrite later, after the
-  // boot LEDs are no longer needed.
+  // The boot sequence drives the LEDs via digitalWrite throughout.
+  // analogWrite() must not be called on these pins before powerOff(),
+  // because on the Adafruit nRF52 core it routes the pin to the PWM
+  // peripheral and subsequent digitalWrite() calls no longer drive it.
   pinMode(PIN_USER_BTN, INPUT_PULLUP);
   pinMode(PIN_LED_RED,  OUTPUT);
   pinMode(PIN_LED_BLUE, OUTPUT);
@@ -107,35 +94,31 @@ void ThinkNodeM6Board::begin() {
   digitalWrite(PIN_LED_BLUE, LOW);
   delay(20);  // pin settle / debounce
 
-  // Decide whether to actually boot based on three signals:
-  //   - RESETPIN bit set → user pressed reset → boot
-  //   - OFF bit set → SENSE-LOW wake (only configured on PIN_USER_BTN) →
-  //     user pressed the Function Button → boot
-  //   - !g_m6_was_powered → GPREGRET2 magic was cleared by full power loss,
-  //     so this is a recovery from a dead battery / solar recharge → boot
-  //     automatically (important for unattended deployments)
-  // Otherwise (POR/brownout/USB transient while we were already running) →
-  // re-sleep silently.
+  // Boot decision:
+  //   g_m6_was_shutdown && no button wake => the user deliberately powered
+  //     off and isn't asking to come back. Stay asleep.
+  //   otherwise => boot (fresh power-up, dead-battery recovery, transient
+  //     reset of a running device, reset pin, or Function-Button wake).
   bool from_reset_pin   = (g_m6_reset_reason & POWER_RESETREAS_RESETPIN_Msk) != 0;
   bool from_button_wake = (g_m6_reset_reason & POWER_RESETREAS_OFF_Msk)      != 0;
-  bool from_power_loss  = !g_m6_was_powered;
 
-  if (!from_reset_pin && !from_button_wake && !from_power_loss) {
-    // No deliberate user action and we were already powered — re-sleep.
+  if (g_m6_was_shutdown && !from_reset_pin && !from_button_wake) {
     enterDeepSleep();
   }
 
-  // Boot indicator: both LEDs full bright for 1 second.
+  // Clear the user-intent flag now that we've committed to booting, so the
+  // next reset starts from a clean "I'm running" state.
+  NRF_POWER->GPREGRET2 = 0;
+
+  // Boot indicator: both LEDs full bright for 1 s.
   digitalWrite(PIN_LED_RED,  HIGH);
   digitalWrite(PIN_LED_BLUE, HIGH);
   delay(1000);
   digitalWrite(PIN_LED_RED,  LOW);
   digitalWrite(PIN_LED_BLUE, LOW);
 
-  // 1-second gap (LEDs off), then start the boot-phase indicator: red solid
-  // on, blue flickering like a disk-drive activity LED. The flicker runs on
-  // a TIMER2 interrupt so it keeps going through every blocking call in
-  // setup() (the_mesh.begin() etc.). It's stopped by bootComplete() at the end.
+  // 1-second gap, then red solid + blue disk-activity flicker. The flicker
+  // runs in the background via TIMER2 until bootComplete() stops it.
   delay(1000);
   digitalWrite(PIN_LED_RED, HIGH);
   startBootFlicker();
@@ -155,27 +138,27 @@ void ThinkNodeM6Board::powerOff() {
   digitalWrite(P_LORA_TX_LED, LOW);
 #endif
 
-  // Shutdown cue: red full bright for 1 s.
+  // Shutdown cue: red full bright for 1 s, then a brief both-LED flash.
   analogWrite(PIN_LED_BLUE, 0);
   analogWrite(PIN_LED_RED,  255);
   delay(1000);
   analogWrite(PIN_LED_RED, 0);
-
-  // Final "goodbye": brief both-LED flash so the user knows we're committed
-  // and the device is going dark right now.
   analogWrite(PIN_LED_RED,  255);
   analogWrite(PIN_LED_BLUE, 255);
   delay(50);
   analogWrite(PIN_LED_RED,  0);
   analogWrite(PIN_LED_BLUE, 0);
 
-  // If the button is still held, we can't yet enter SYSTEMOFF (SENSE-LOW
-  // would wake us immediately). Wait silently for release — no LEDs lit,
-  // so the wait is invisible.
+  // SENSE-LOW would fire immediately if we enter SYSTEMOFF with the button
+  // still held — wait for release first.
   while (digitalRead(PIN_USER_BTN) == LOW) delay(10);
 
   Serial.flush();
   delay(50);
+
+  // User-intent magic byte; read by variant.cpp's early constructor.
+  NRF_POWER->GPREGRET2 = 0xA5;
+
   enterDeepSleep();
 }
 
@@ -196,9 +179,7 @@ uint16_t ThinkNodeM6Board::getBattMilliVolts() {
 }
 
 void ThinkNodeM6Board::bootComplete() {
-  // Stop the flicker timer, turn red off, pause 1 second (everything dark)
-  // to clearly delimit the boot phase, then flash blue for 100 ms as the
-  // "device is up" signal.
+  // Stop the disk-activity flicker, dark 1 s gap, then 100 ms blue flash.
   stopBootFlicker();
   digitalWrite(PIN_LED_RED,  LOW);
   digitalWrite(PIN_LED_BLUE, LOW);
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.h b/variants/thinknode_m6/ThinkNodeM6Board.h
index 26b2d89e20..6e4c9e062e 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.h
+++ b/variants/thinknode_m6/ThinkNodeM6Board.h
@@ -23,9 +23,8 @@ class ThinkNodeM6Board : public NRF52BoardDCDC {
   void begin();
   uint16_t getBattMilliVolts() override;
 
-  // Called at the very end of setup() to mark "boot complete": stops the
-  // disk-activity-style blue flicker started in begin(), turns the red LED
-  // off, and flashes the blue LED for 100 ms.
+  // Called at the end of setup(). Stops the disk-activity blue flicker
+  // started in begin() and flashes the blue LED briefly.
   void bootComplete();
 
 #if defined(P_LORA_TX_LED)
diff --git a/variants/thinknode_m6/variant.cpp b/variants/thinknode_m6/variant.cpp
index 4c1ac98262..1473db4b10 100644
--- a/variants/thinknode_m6/variant.cpp
+++ b/variants/thinknode_m6/variant.cpp
@@ -3,35 +3,27 @@
 #include "wiring_digital.h"
 #include "nrf.h"
 
-// Capture NRF_POWER->RESETREAS before SystemInit() runs the Nordic errata-136
-// workaround that clears the RESETPIN bit. Priority 101 places this before
-// SystemInit (102) and all C++ static constructors. Exposed via the globals
-// below so ThinkNodeM6Board::begin() can decide whether to boot or re-sleep.
+// Globals captured early — before SystemInit()'s errata-136 workaround
+// clears the RESETPIN bit, and before any C++ static constructors. Priority
+// 101 runs before SystemInit (102).
 //
-// We also leverage GPREGRET2 (an 8-bit retained register) to detect full
-// power loss: the register persists through SYSTEMOFF but is cleared when
-// the chip loses power completely. By stamping a magic value on every boot,
-// the next boot can tell "we cleanly went to SYSTEMOFF" (magic still there)
-// from "battery died and just came back" (magic cleared). The latter case
-// boots automatically — important for unattended solar-powered deployments.
+// g_m6_reset_reason: snapshot of NRF_POWER->RESETREAS.
+// g_m6_was_shutdown: true if GPREGRET2 holds the "user-intent" magic byte.
 //
-// NOTE: GPREGRET2 is also written by NRF52Board::enterSystemOff() when
-// NRF52_POWER_MANAGEMENT is defined. That build flag is NOT set for any M6
-// env today, so there is no conflict. If it's ever enabled for the M6, the
-// magic value here will collide with the shutdown-reason byte stored there.
-#define M6_GPREGRET2_MAGIC      0xA5
+// GPREGRET2 is used as a user-intent flag: powerOff() writes 0xA5 right
+// before SYSTEMOFF, board.begin() clears it on a successful boot. It
+// persists across SYSTEMOFF but is wiped by a true power-on reset.
+//
+// NOTE: GPREGRET2 is also written by NRF52Board::enterSystemOff() under the
+// NRF52_POWER_MANAGEMENT build flag. That flag is not set for any M6 env;
+// if it ever is, the byte stored here will collide.
 volatile uint32_t g_m6_reset_reason  = 0;
-volatile bool     g_m6_was_powered   = false;
+volatile bool     g_m6_was_shutdown  = false;
 
 extern "C" __attribute__((constructor(101))) void m6_capture_resetreas(void) {
   g_m6_reset_reason = NRF_POWER->RESETREAS;
-  // Clear sticky bits so the next boot sees a fresh state.
-  NRF_POWER->RESETREAS = 0xFFFFFFFFul;
-
-  // GPREGRET2 magic value: present = firmware ran in this power session
-  // (we cleanly went to SYSTEMOFF and came back); absent = power was lost.
-  g_m6_was_powered = (NRF_POWER->GPREGRET2 == M6_GPREGRET2_MAGIC);
-  NRF_POWER->GPREGRET2 = M6_GPREGRET2_MAGIC;  // stamp it for next boot
+  NRF_POWER->RESETREAS = 0xFFFFFFFFul;  // clear sticky bits
+  g_m6_was_shutdown = (NRF_POWER->GPREGRET2 == 0xA5);
 }
 
 const uint32_t g_ADigitalPinMap[] = {

From 6b4dfbbfcc6061dc24a265e11306d4917269f35b Mon Sep 17 00:00:00 2001
From: AtlavoxDev <matt@bizfound.com>
Date: Fri, 22 May 2026 12:30:30 -0400
Subject: [PATCH 5/6] Clean up main.cpp

Remove device-specific code from the universal main.cpp file
---
 examples/simple_repeater/main.cpp          | 71 ++--------------------
 variants/thinknode_m6/ThinkNodeM6Board.cpp | 62 +++++++++++++++++++
 variants/thinknode_m6/ThinkNodeM6Board.h   |  9 +++
 3 files changed, 75 insertions(+), 67 deletions(-)

diff --git a/examples/simple_repeater/main.cpp b/examples/simple_repeater/main.cpp
index 00f2624b03..ded847af6d 100644
--- a/examples/simple_repeater/main.cpp
+++ b/examples/simple_repeater/main.cpp
@@ -28,36 +28,12 @@ static unsigned long userBtnDownAt = 0;
 #define USER_BTN_HOLD_OFF_MILLIS 1500
 #endif
 
-#if defined(PIN_USER_BTN) && defined(THINKNODE_M6)
-static unsigned long m6BtnDownAt = 0;
-// Long-press shutdown: red LED flashes briefly at 0 s and 1 s during the
-// hold, then board.powerOff() runs the final shutdown cue at 2 s.
-#define M6_OFF_FLASH1_START_MS  0
-#define M6_OFF_FLASH1_END_MS    200
-#define M6_OFF_FLASH2_START_MS  1000
-#define M6_OFF_FLASH2_END_MS    1200
-#define M6_OFF_COMMIT_MS        2000
-#define M6_OFF_FLASH_BRIGHT     128   // ~50% of 255
-
-// Quick tap (press+release) sends an advert; blue LED blinks Morse "A".
-#define M6_TAP_MIN_MS           30    // debounce floor
-#define M6_TAP_MAX_MS           500   // anything longer is a hold attempt
-#define M6_MORSE_DOT_MS         200
-#define M6_MORSE_GAP_MS         200
-#define M6_MORSE_DASH_MS        600
-#endif
 
 void setup() {
   Serial.begin(115200);
-
-#ifdef THINKNODE_M6
-  // M6's board.begin() drives the boot LED sequence; run it before any
-  // pre-setup delays so the LEDs come on immediately at wake.
-  board.begin();
-#else
   delay(1000);
+
   board.begin();
-#endif
 
 #if defined(MESH_DEBUG) && defined(NRF52_PLATFORM)
   // give some extra time for serial to settle so
@@ -176,48 +152,9 @@ void loop() {
   }
 #endif
 
-#if defined(PIN_USER_BTN) && defined(THINKNODE_M6)
-  // Hold Function Button to power off the ThinkNode M6.
-  {
-    int btnState = digitalRead(PIN_USER_BTN);
-    if (btnState == LOW) {
-      if (m6BtnDownAt == 0) {
-        m6BtnDownAt = millis();
-      }
-      unsigned long held = millis() - m6BtnDownAt;
-
-      if (held >= M6_OFF_COMMIT_MS) {
-        Serial.println("Powering off...");
-        board.powerOff();  // does not return
-      } else if ((held >= M6_OFF_FLASH1_START_MS && held < M6_OFF_FLASH1_END_MS) ||
-                 (held >= M6_OFF_FLASH2_START_MS && held < M6_OFF_FLASH2_END_MS)) {
-        analogWrite(PIN_LED_RED,    M6_OFF_FLASH_BRIGHT);
-        digitalWrite(PIN_LED_BLUE,  LOW);
-      } else {
-        analogWrite(PIN_LED_RED,    0);
-        digitalWrite(PIN_LED_BLUE,  LOW);
-      }
-    } else {
-      // Button released. Quick press+release = tap (send advert). Longer
-      // holds that don't reach the commit threshold are silent cancels.
-      if (m6BtnDownAt != 0) {
-        unsigned long held = millis() - m6BtnDownAt;
-        analogWrite(PIN_LED_RED,    0);
-        digitalWrite(PIN_LED_BLUE,  LOW);
-
-        if (held >= M6_TAP_MIN_MS && held < M6_TAP_MAX_MS) {
-          // Tap → advert + Morse "A" on blue. digitalWrite keeps blue in
-          // pure GPIO mode so the LoRa TX LED indicator still works.
-          Serial.println("Tap -> sending advert");
-          the_mesh.sendSelfAdvertisement(16000, false);
-          digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DOT_MS);
-          digitalWrite(PIN_LED_BLUE, LOW);  delay(M6_MORSE_GAP_MS);
-          digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DASH_MS);
-          digitalWrite(PIN_LED_BLUE, LOW);
-        }
-      }
-      m6BtnDownAt = 0;
-    }
+#ifdef THINKNODE_M6
+  if (board.checkButton()) {
+    the_mesh.sendSelfAdvertisement(16000, false);
   }
 #endif
 
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.cpp b/variants/thinknode_m6/ThinkNodeM6Board.cpp
index d42efdecdb..b378a3174d 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.cpp
+++ b/variants/thinknode_m6/ThinkNodeM6Board.cpp
@@ -5,6 +5,23 @@
 
 #include <Wire.h>
 
+// Function-button timing constants (used by checkButton()).
+//   Long-press shutdown: brief red blink at 0 s and 1 s during the hold,
+//   then board.powerOff() runs the final cue when held past 2 s.
+#define M6_OFF_FLASH1_START_MS  0
+#define M6_OFF_FLASH1_END_MS    200
+#define M6_OFF_FLASH2_START_MS  1000
+#define M6_OFF_FLASH2_END_MS    1200
+#define M6_OFF_COMMIT_MS        2000
+#define M6_OFF_FLASH_BRIGHT     128   // ~50% of 255
+
+// Quick tap (press+release) sends an advert; blue blinks Morse "A".
+#define M6_TAP_MIN_MS           30    // debounce floor
+#define M6_TAP_MAX_MS           500   // anything longer is a hold attempt
+#define M6_MORSE_DOT_MS         200
+#define M6_MORSE_GAP_MS         200
+#define M6_MORSE_DASH_MS        600
+
 // Boot-phase blue LED flicker. TIMER2 fires at pseudo-random 10-100 ms
 // intervals; the ISR toggles the blue LED. Runs in the background through
 // every blocking call in setup() (mesh init, etc.).
@@ -189,4 +206,49 @@ void ThinkNodeM6Board::bootComplete() {
   digitalWrite(PIN_LED_BLUE, LOW);
 }
 
+bool ThinkNodeM6Board::checkButton() {
+  int btnState = digitalRead(PIN_USER_BTN);
+  if (btnState == LOW) {
+    if (_btn_down_at == 0) {
+      _btn_down_at = millis();
+    }
+    unsigned long held = millis() - _btn_down_at;
+
+    if (held >= M6_OFF_COMMIT_MS) {
+      Serial.println("Powering off...");
+      powerOff();  // does not return
+    } else if ((held >= M6_OFF_FLASH1_START_MS && held < M6_OFF_FLASH1_END_MS) ||
+               (held >= M6_OFF_FLASH2_START_MS && held < M6_OFF_FLASH2_END_MS)) {
+      analogWrite(PIN_LED_RED,    M6_OFF_FLASH_BRIGHT);
+      digitalWrite(PIN_LED_BLUE,  LOW);
+    } else {
+      analogWrite(PIN_LED_RED,    0);
+      digitalWrite(PIN_LED_BLUE,  LOW);
+    }
+    return false;
+  }
+
+  // Button released. Quick press+release = tap (send advert). Longer
+  // holds that don't reach the commit threshold are silent cancels.
+  bool was_tap = false;
+  if (_btn_down_at != 0) {
+    unsigned long held = millis() - _btn_down_at;
+    analogWrite(PIN_LED_RED,    0);
+    digitalWrite(PIN_LED_BLUE,  LOW);
+
+    if (held >= M6_TAP_MIN_MS && held < M6_TAP_MAX_MS) {
+      // Tap → run Morse "A" ack on blue. digitalWrite keeps blue in pure
+      // GPIO mode so the LoRa TX LED indicator still works afterwards.
+      Serial.println("Tap -> sending advert");
+      digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DOT_MS);
+      digitalWrite(PIN_LED_BLUE, LOW);  delay(M6_MORSE_GAP_MS);
+      digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DASH_MS);
+      digitalWrite(PIN_LED_BLUE, LOW);
+      was_tap = true;
+    }
+  }
+  _btn_down_at = 0;
+  return was_tap;
+}
+
 #endif
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.h b/variants/thinknode_m6/ThinkNodeM6Board.h
index 6e4c9e062e..cdad4a1eb3 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.h
+++ b/variants/thinknode_m6/ThinkNodeM6Board.h
@@ -18,6 +18,9 @@ class ThinkNodeM6Board : public NRF52BoardDCDC {
   void initiateShutdown(uint8_t reason) override;
 #endif
 
+private:
+  unsigned long _btn_down_at = 0;  // function-button press timestamp (0 = not pressed)
+
 public:
   ThinkNodeM6Board() : NRF52Board("THINKNODE_M6_OTA") {}
   void begin();
@@ -27,6 +30,12 @@ class ThinkNodeM6Board : public NRF52BoardDCDC {
   // started in begin() and flashes the blue LED briefly.
   void bootComplete();
 
+  // Polls the function button. Drives all LED feedback during a hold,
+  // calls powerOff() internally on a long press, and runs the Morse "A"
+  // ack blink on a quick tap.
+  // Returns true on a tap — caller should broadcast a self-advertisement.
+  bool checkButton();
+
 #if defined(P_LORA_TX_LED)
   void onBeforeTransmit() override {
     digitalWrite(P_LORA_TX_LED, HIGH);   // turn TX LED on

From 53d663f084b0683ca58876bb1f4783ee1f258ee9 Mon Sep 17 00:00:00 2001
From: AtlavoxDev <matt@bizfound.com>
Date: Fri, 22 May 2026 13:26:10 -0400
Subject: [PATCH 6/6] Tread lightly in main.cpp
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The M6 follows a cleaner version of the existing SenseCAP Solar pattern: device-specific button logic lives in the variant (ThinkNodeM6Board::pollButton()), with a minimal dispatch call in main.cpp. The buttonStateChanged() methods on ThinkNodeM3Board, T1000eBoard, and PromicroBoard were defined but never connected to any caller — those boards could adopt the same pollButton() pattern in follow-up PRs if button UX is wanted.
---
 examples/simple_repeater/main.cpp          |  5 +--
 variants/thinknode_m6/ThinkNodeM6Board.cpp | 43 +++++-----------------
 variants/thinknode_m6/ThinkNodeM6Board.h   |  8 ++--
 3 files changed, 14 insertions(+), 42 deletions(-)

diff --git a/examples/simple_repeater/main.cpp b/examples/simple_repeater/main.cpp
index ded847af6d..bcfce951a7 100644
--- a/examples/simple_repeater/main.cpp
+++ b/examples/simple_repeater/main.cpp
@@ -28,7 +28,6 @@ static unsigned long userBtnDownAt = 0;
 #define USER_BTN_HOLD_OFF_MILLIS 1500
 #endif
 
-
 void setup() {
   Serial.begin(115200);
   delay(1000);
@@ -153,9 +152,7 @@ void loop() {
 #endif
 
 #ifdef THINKNODE_M6
-  if (board.checkButton()) {
-    the_mesh.sendSelfAdvertisement(16000, false);
-  }
+  board.pollButton();
 #endif
 
   the_mesh.loop();
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.cpp b/variants/thinknode_m6/ThinkNodeM6Board.cpp
index b378a3174d..e1cd86acd9 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.cpp
+++ b/variants/thinknode_m6/ThinkNodeM6Board.cpp
@@ -5,9 +5,9 @@
 
 #include <Wire.h>
 
-// Function-button timing constants (used by checkButton()).
-//   Long-press shutdown: brief red blink at 0 s and 1 s during the hold,
-//   then board.powerOff() runs the final cue when held past 2 s.
+// Function-button timing for hold-to-power-off.
+//   Brief red blink at 0 s and 1 s during the hold, then board.powerOff()
+//   runs the final cue when held past 2 s.
 #define M6_OFF_FLASH1_START_MS  0
 #define M6_OFF_FLASH1_END_MS    200
 #define M6_OFF_FLASH2_START_MS  1000
@@ -15,13 +15,6 @@
 #define M6_OFF_COMMIT_MS        2000
 #define M6_OFF_FLASH_BRIGHT     128   // ~50% of 255
 
-// Quick tap (press+release) sends an advert; blue blinks Morse "A".
-#define M6_TAP_MIN_MS           30    // debounce floor
-#define M6_TAP_MAX_MS           500   // anything longer is a hold attempt
-#define M6_MORSE_DOT_MS         200
-#define M6_MORSE_GAP_MS         200
-#define M6_MORSE_DASH_MS        600
-
 // Boot-phase blue LED flicker. TIMER2 fires at pseudo-random 10-100 ms
 // intervals; the ISR toggles the blue LED. Runs in the background through
 // every blocking call in setup() (mesh init, etc.).
@@ -206,7 +199,7 @@ void ThinkNodeM6Board::bootComplete() {
   digitalWrite(PIN_LED_BLUE, LOW);
 }
 
-bool ThinkNodeM6Board::checkButton() {
+void ThinkNodeM6Board::pollButton() {
   int btnState = digitalRead(PIN_USER_BTN);
   if (btnState == LOW) {
     if (_btn_down_at == 0) {
@@ -225,30 +218,14 @@ bool ThinkNodeM6Board::checkButton() {
       analogWrite(PIN_LED_RED,    0);
       digitalWrite(PIN_LED_BLUE,  LOW);
     }
-    return false;
-  }
-
-  // Button released. Quick press+release = tap (send advert). Longer
-  // holds that don't reach the commit threshold are silent cancels.
-  bool was_tap = false;
-  if (_btn_down_at != 0) {
-    unsigned long held = millis() - _btn_down_at;
-    analogWrite(PIN_LED_RED,    0);
-    digitalWrite(PIN_LED_BLUE,  LOW);
-
-    if (held >= M6_TAP_MIN_MS && held < M6_TAP_MAX_MS) {
-      // Tap → run Morse "A" ack on blue. digitalWrite keeps blue in pure
-      // GPIO mode so the LoRa TX LED indicator still works afterwards.
-      Serial.println("Tap -> sending advert");
-      digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DOT_MS);
-      digitalWrite(PIN_LED_BLUE, LOW);  delay(M6_MORSE_GAP_MS);
-      digitalWrite(PIN_LED_BLUE, HIGH); delay(M6_MORSE_DASH_MS);
-      digitalWrite(PIN_LED_BLUE, LOW);
-      was_tap = true;
+  } else {
+    // Button released before commit — clear LEDs and reset state.
+    if (_btn_down_at != 0) {
+      analogWrite(PIN_LED_RED,    0);
+      digitalWrite(PIN_LED_BLUE,  LOW);
     }
+    _btn_down_at = 0;
   }
-  _btn_down_at = 0;
-  return was_tap;
 }
 
 #endif
diff --git a/variants/thinknode_m6/ThinkNodeM6Board.h b/variants/thinknode_m6/ThinkNodeM6Board.h
index cdad4a1eb3..a209ac9101 100644
--- a/variants/thinknode_m6/ThinkNodeM6Board.h
+++ b/variants/thinknode_m6/ThinkNodeM6Board.h
@@ -30,11 +30,9 @@ class ThinkNodeM6Board : public NRF52BoardDCDC {
   // started in begin() and flashes the blue LED briefly.
   void bootComplete();
 
-  // Polls the function button. Drives all LED feedback during a hold,
-  // calls powerOff() internally on a long press, and runs the Morse "A"
-  // ack blink on a quick tap.
-  // Returns true on a tap — caller should broadcast a self-advertisement.
-  bool checkButton();
+  // Polls the function button. Drives LED feedback during a hold and
+  // calls powerOff() internally on a long press (>= 2 s).
+  void pollButton();
 
 #if defined(P_LORA_TX_LED)
   void onBeforeTransmit() override {