Improve brownout recovery

.gitignore

@@ -17,3 +17,4 @@ compile_commands.json
 .venv/
 venv/
 platformio.local.ini
+Pipfile

boards/nrf52840_s140_v6.ld

@@ -33,6 +33,13 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
+
+  .noinit (NOLOAD) :
+  {
+    . = ALIGN(4);
+    KEEP(*(.noinit))
+    . = ALIGN(4);
+  } > RAM
 } INSERT AFTER .data;
 
 INCLUDE "nrf52_common.ld"

boards/nrf52840_s140_v6_extrafs.ld

@@ -33,6 +33,13 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
+
+  .noinit (NOLOAD) :
+  {
+    . = ALIGN(4);
+    KEEP(*(.noinit))
+    . = ALIGN(4);
+  } > RAM
 } INSERT AFTER .data;
 
 INCLUDE "nrf52_common.ld"

boards/nrf52840_s140_v7.ld

@@ -33,6 +33,13 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
+
+  .noinit (NOLOAD) :
+  {
+    . = ALIGN(4);
+    KEEP(*(.noinit))
+    . = ALIGN(4);
+  } > RAM
 } INSERT AFTER .data;
 
 INCLUDE "nrf52_common.ld"

boards/nrf52840_s140_v7_extrafs.ld

@@ -33,6 +33,13 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
+
+  .noinit (NOLOAD) :
+  {
+    . = ALIGN(4);
+    KEEP(*(.noinit))
+    . = ALIGN(4);
+  } > RAM
 } INSERT AFTER .data;
 
 INCLUDE "nrf52_common.ld"

docs/cli_commands.md

@@ -1107,6 +1107,26 @@ region save
 #### View the current power source
 **Usage:** `get pwrmgt.source`
 
+Returns a composite source and confidence state, for example `vusb+bat:valid`,
+`vusb-only:valid`, `bat-only:implausible`, or `vusb-only:possible-battery`.
+
+Confidence thresholds are board-configured in `PowerMgtConfig`. The current
+nRF52 power-management board configs all set `battery_min_present_mv = 1000`,
+`battery_min_plausible_mv = 2500`
+and `battery_max_plausible_mv = 4500`, so BAT voltage is `valid` from 2500mV
+to 4500mV inclusive. Readings outside that range are `implausible`, boards with
+unusable BAT sensing report `invalid`, and missing power-management
+configuration reports `unknown`. VUSB has no configured millivolt thresholds;
+it is detected through the nRF52 `USBREGSTATUS.VBUSDETECT` hardware signal.
+BAT readings below 1000mV are treated as absent/floating for boot-lock
+decisions and are not reported as a BAT source. With VBUS detected this reports
+`vusb-only:valid`; without VBUS detect this reports `vusb-only:possible-battery`.
+Readings from 1000mV up to the boot-lock threshold still trigger protective
+shutdown; high readings above 4500mV are treated as unsafe evidence.
+If a battery is connected to VUSB and falls below the hardware VBUS-detect
+point while still powering the MCU, the source is reported as
+`vusb-only:possible-battery`.
+
 **Note:** Returns an error on boards without power management support.
 
 ---
@@ -1121,6 +1141,26 @@ region save
 #### View the boot voltage
 **Usage:** `get pwrmgt.bootmv`
 
+Adds `invalid` when the board configuration marks BAT voltage sensing as
+untrusted, for example `> 426 mV invalid`.
+
 **Note:** Returns an error on boards without power management support.
 
 ---
+
+#### View the last radio initialisation status
+**Usage:** `get radio.init_status`
+
+---
+
+#### View the radio initialisation attempt count
+**Usage:** `get radio.init_attempts`
+
+---
+
+#### View compact boot diagnostics
+**Usage:** `get diag.boot`
+
+**Note:** Returns current and previous reset-retained boot diagnostics. `cur_sd` and `prev_sd` are raw shutdown/fault markers, including low voltage, boot protection, user shutdown, and radio initialisation failure.
+
+---

src/MeshCore.h

@@ -67,7 +67,9 @@ class MainBoard {
 
   // Power management interface (boards with power management override these)
   virtual bool isExternalPowered() { return false; }
+  virtual const char* getPowerSourceState() { return isExternalPowered() ? "vusb-only:unknown" : "none:unknown"; }
   virtual uint16_t getBootVoltage() { return 0; }
+  virtual bool isBootVoltageValid() { return false; }
   virtual uint32_t getResetReason() const { return 0; }
   virtual const char* getResetReasonString(uint32_t reason) { return "Not available"; }
   virtual uint8_t getShutdownReason() const { return 0; }

src/helpers/CommonCLI.cpp

@@ -3,6 +3,7 @@
 #include "TxtDataHelpers.h"
 #include "AdvertDataHelpers.h"
 #include "TxtDataHelpers.h"
+#include "RadioInitDiagnostics.h"
 #include <RTClib.h>
 
 #ifndef BRIDGE_MAX_BAUD
@@ -908,7 +909,7 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
 #endif
   } else if (memcmp(config, "pwrmgt.source", 13) == 0) {
 #ifdef NRF52_POWER_MANAGEMENT
-    strcpy(reply, _board->isExternalPowered() ? "> external" : "> battery");
+    sprintf(reply, "> %s", _board->getPowerSourceState());
 #else
     strcpy(reply, "ERROR: Power management not supported");
 #endif
@@ -922,10 +923,29 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
 #endif
   } else if (memcmp(config, "pwrmgt.bootmv", 13) == 0) {
 #ifdef NRF52_POWER_MANAGEMENT
-    sprintf(reply, "> %u mV", _board->getBootVoltage());
+    sprintf(reply, _board->isBootVoltageValid() ? "> %u mV" : "> %u mV invalid",
+      _board->getBootVoltage());
 #else
     strcpy(reply, "ERROR: Power management not supported");
 #endif
+  } else if (memcmp(config, "radio.init_status", 17) == 0) {
+    sprintf(reply, "> %d", (int)g_last_radio_init_status);
+  } else if (memcmp(config, "radio.init_attempts", 19) == 0) {
+    sprintf(reply, "> %u", (unsigned)g_radio_init_attempts);
+  } else if (memcmp(config, "diag.boot", 9) == 0) {
+    RadioInitBootRecord cur = radioInitCurrentBootRecord();
+    RadioInitBootRecord prev = radioInitPreviousBootRecord();
+    sprintf(reply, "> cur_rr=0x%08lX cur_sd=0x%02X cur_st=0x%02X cur_radio=%d cur_att=%u prev_rr=0x%08lX prev_sd=0x%02X prev_st=0x%02X prev_radio=%d prev_att=%u",
+      (unsigned long)cur.reset_reason,
+      (unsigned)cur.shutdown_reason,
+      (unsigned)cur.boot_stage,
+      (int)cur.radio_status,
+      (unsigned)cur.attempts,
+      (unsigned long)prev.reset_reason,
+      (unsigned)prev.shutdown_reason,
+      (unsigned)prev.boot_stage,
+      (int)prev.radio_status,
+      (unsigned)prev.attempts);
   } else {
     sprintf(reply, "??: %s", config);
   }