fix: silence false-alarm boot log errors from NVS and accelerometer probe

src/accelerometer.cpp

@@ -70,6 +70,20 @@ bool readRegister(uint8_t reg, uint8_t *outValue) {
 bool Accelerometer::begin() {
   Wire.begin(PinAssignment::kI2cSda, PinAssignment::kI2cScl);
 
+  // Plain presence probe (address-only write, real stop condition)
+  // before attempting the repeated-start register read below. On boards
+  // without this part (the first production run — see
+  // PCB/GPIO_table.md's Accelerometer section) endTransmission(false)'s
+  // repeated-start check doesn't reliably report the missing ACK by
+  // itself — a known ESP32 I2C driver quirk — so without this,
+  // Wire.requestFrom() gets called against a device that was never
+  // there, which the Wire library logs as an alarming-looking error.
+  Wire.beginTransmission(kI2cAddress);
+  if (Wire.endTransmission() != 0) {
+    present_ = false;
+    return false;
+  }
+
   uint8_t chipId = 0;
   if (!readRegister(kRegChipId, &chipId)) {
     present_ = false;

src/calibration_store.cpp

@@ -10,7 +10,15 @@ CalibrationData CalibrationStore::load() {
   CalibrationData data;  // defaults if nothing has been saved yet
 
   Preferences prefs;
-  if (!prefs.begin(kNamespace, /*readOnly=*/true)) {
+  // Not readOnly: on a device that's never saved this namespace yet
+  // (first boot, or after a flash-partition wipe), NVS_READONLY makes
+  // nvs_open() fail with ESP_ERR_NVS_NOT_FOUND, which the Preferences
+  // library logs as an alarming-looking error regardless of how
+  // gracefully the caller handles the resulting begin() == false (we
+  // just fall back to defaults either way). Opening read-write instead
+  // creates the empty namespace silently — no behavior change, no false
+  // "hardware is broken" errors on real hardware's first boot.
+  if (!prefs.begin(kNamespace, /*readOnly=*/false)) {
     return data;
   }
 

src/complication_persistence.cpp

@@ -10,7 +10,10 @@ constexpr const char *kNamespace = "snips_disp";
 
 void ComplicationPersistence::load(ComplicationRegistry *registry) {
   Preferences prefs;
-  if (!prefs.begin(kNamespace, /*readOnly=*/true)) {
+  // Not readOnly: avoids a misleading "nvs_open failed: NOT_FOUND" log
+  // on a device that's never saved this namespace yet — see
+  // calibration_store.cpp's load() for the full explanation.
+  if (!prefs.begin(kNamespace, /*readOnly=*/false)) {
     return;
   }
 

src/droid_persistence.cpp

@@ -12,7 +12,10 @@ DroidStore DroidPersistence::load() {
   DroidStore store;
 
   Preferences prefs;
-  if (!prefs.begin(kNamespace, /*readOnly=*/true)) {
+  // Not readOnly: avoids a misleading "nvs_open failed: NOT_FOUND" log
+  // on a device that's never saved this namespace yet — see
+  // calibration_store.cpp's load() for the full explanation.
+  if (!prefs.begin(kNamespace, /*readOnly=*/false)) {
     return store;
   }
 

src/power_config_store.cpp

@@ -10,7 +10,10 @@ PowerConfig PowerConfigStore::load() {
   PowerConfig config;  // defaults if nothing has been saved yet
 
   Preferences prefs;
-  if (!prefs.begin(kNamespace, /*readOnly=*/true)) {
+  // Not readOnly: avoids a misleading "nvs_open failed: NOT_FOUND" log
+  // on a device that's never saved this namespace yet — see
+  // calibration_store.cpp's load() for the full explanation.
+  if (!prefs.begin(kNamespace, /*readOnly=*/false)) {
     return config;
   }