diff --git a/src/platform/nrf52/main-nrf52.cpp b/src/platform/nrf52/main-nrf52.cpp
index c705521ad..af65446b4 100644
--- a/src/platform/nrf52/main-nrf52.cpp
+++ b/src/platform/nrf52/main-nrf52.cpp
@@ -45,6 +45,7 @@
 #endif
 
 uint16_t getVDDVoltage();
+void cpuDeepSleep(uint32_t msecToWake);
 
 // Weak empty variant shutdown prep function.
 // May be redefined by variant files.
@@ -75,7 +76,7 @@ bool powerHAL_isVBUSConnected()
 bool powerHAL_isPowerLevelSafe()
 {
 
-    static bool powerLevelSafe = true;
+    static bool powerLevelSafe = true;  
 
     uint16_t threshold = SAFE_VDD_VOLTAGE_THRESHOLD * 1000; // convert V to mV
     uint16_t hysteresis = SAFE_VDD_VOLTAGE_THRESHOLD_HYST * 1000;
@@ -326,6 +327,24 @@ void nrf52Loop()
 
     checkSDEvents();
     reportLittleFSCorruptionOnce();
+
+#ifdef LOW_VDD_SYSTEMOFF_DELAY_MS   // rak_wismeshtag does not have a USB VBUS connected
+    // If VDD stays unsafe for a while (typically during brownout),
+    // force System OFF to avoid flash writes / SoftDevice instability loops.
+    // Skip when VBUS is present to allow recovery while USB-powered.
+    if (!powerHAL_isVBUSConnected()) {
+        static uint32_t low_vdd_since_ms = 0;
+        if (!powerHAL_isPowerLevelSafe()) {
+            if (low_vdd_since_ms == 0)
+                low_vdd_since_ms = millis();
+            if ((uint32_t)(millis() - low_vdd_since_ms) >= (uint32_t)LOW_VDD_SYSTEMOFF_DELAY_MS) {
+                cpuDeepSleep(portMAX_DELAY);
+            }
+        } else {
+            low_vdd_since_ms = 0;
+        }
+    }
+#endif
 }
 
 #ifdef USE_SEMIHOSTING
diff --git a/variants/nrf52840/rak_wismeshtag/variant.h b/variants/nrf52840/rak_wismeshtag/variant.h
index 5b20e4d93..6014af871 100644
--- a/variants/nrf52840/rak_wismeshtag/variant.h
+++ b/variants/nrf52840/rak_wismeshtag/variant.h
@@ -225,7 +225,29 @@ SO GPIO 39/TXEN MAY NOT BE DEFINED FOR SUCCESSFUL OPERATION OF THE SX1262 - TG
 #define AREF_VOLTAGE 3.0
 #define VBAT_AR_INTERNAL AR_INTERNAL_3_0
 #define ADC_MULTIPLIER 1.73
-#define OCV_ARRAY 4240, 4112, 4029, 3970, 3906, 3846, 3824, 3802, 3776, 3650, 3072
+#define OCV_ARRAY 4160, 4020, 3940, 3870, 3810, 3760, 3740, 3720, 3680, 3620, 2990  // updated OCV array for rak_wismeshtag
+
+// Wake from System OFF when battery rises again (LPCOMP).
+// BAT_ADC divider: R22=1M (top), R24=1.5M (bottom) => V_BAT_ADC = VBAT * (1.5 / (1.0 + 1.5)) = 0.6 * VBAT
+// RAK4630 module: AIN0 = nrf52840 AIN3 = Pin 5 (A0/BATTERY_PIN)
+#define BATTERY_LPCOMP_INPUT NRF_LPCOMP_INPUT_3
+// If VDD is regulated ~3.3V, this wakes around VBAT ~3.09V (good for brownout recovery).
+#define BATTERY_LPCOMP_THRESHOLD NRF_LPCOMP_REF_SUPPLY_9_16  //3.09V NRF_LPCOMP_REF_SUPPLY_9_16 = 3.09V
+
+// Low voltage protection:
+// If VDD is below SAFE_VDD_VOLTAGE_THRESHOLD for longer than this delay (and no USB VBUS),
+// the device will enter System OFF to avoid brownout loops and flash corruption.
+#ifndef LOW_VDD_SYSTEMOFF_DELAY_MS
+#define LOW_VDD_SYSTEMOFF_DELAY_MS 5000
+#endif
+
+#ifndef SAFE_VDD_VOLTAGE_THRESHOLD
+#define SAFE_VDD_VOLTAGE_THRESHOLD 2.9
+#endif
+
+#ifndef SAFE_VDD_VOLTAGE_THRESHOLD_HYST
+#define SAFE_VDD_VOLTAGE_THRESHOLD_HYST 0.1
+#endif
 
 #define RAK_4631 1