feat(wio-tracker-l2): internal flash as LittleFS instead of SPIFFS

helpers/esp32/InternalFS.h picks the filesystem: -D ESP32_LITTLEFS mounts
LittleFS on the same "spiffs" partition, otherwise SPIFFS as before. Only the
L2 LVGL envs set it; every other ESP32 board is unchanged. A settings save
drops from ~0.5 s to ~80 ms and the files survive power loss mid-write.
No migration: the first boot formats the partition (fresh identity).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/companion_radio/DataStore.cpp

@@ -81,7 +81,7 @@ void DataStore::begin() {
 }
 
 #if defined(ESP32)
-  #include <SPIFFS.h>
+  #include <helpers/esp32/InternalFS.h>
   #include <nvs_flash.h>
 #elif defined(RP2040_PLATFORM)
   #include <LittleFS.h>
@@ -119,7 +119,7 @@ lfs_ssize_t _getLfsUsedBlockCount(FILESYSTEM* fs) {
 
 uint32_t DataStore::getStorageUsedKb() const {
 #if defined(ESP32)
-  return SPIFFS.usedBytes() / 1024;
+  return ESP32_FS.usedBytes() / 1024;
 #elif defined(RP2040_PLATFORM)
   FSInfo info;
   info.usedBytes = 0;
@@ -137,7 +137,7 @@ uint32_t DataStore::getStorageUsedKb() const {
 
 uint32_t DataStore::getStorageTotalKb() const {
 #if defined(ESP32)
-  return SPIFFS.totalBytes() / 1024;
+  return ESP32_FS.totalBytes() / 1024;
 #elif defined(RP2040_PLATFORM)
   FSInfo info;
   info.totalBytes = 0;
@@ -198,7 +198,7 @@ bool DataStore::formatFileSystem() {
 #elif defined(RP2040_PLATFORM)
   return LittleFS.format();
 #elif defined(ESP32)
-  bool fs_success = ((fs::SPIFFSFS *)_fs)->format();
+  bool fs_success = ((ESP32_FS_CLASS *)_fs)->format();
   esp_err_t nvs_err = nvs_flash_erase(); // no need to reinit, will be done by reboot
   return fs_success && (nvs_err == ESP_OK);
 #elif defined(SIM_PLATFORM)

examples/companion_radio/MyMesh.h

@@ -37,7 +37,7 @@ class UITask;
 #elif defined(RP2040_PLATFORM)
 #include <LittleFS.h>
 #elif defined(ESP32)
-#include <SPIFFS.h>
+#include <helpers/esp32/InternalFS.h>
 #endif
 
 #include "DataStore.h"

examples/companion_radio/main.cpp

@@ -54,8 +54,8 @@ static uint32_t _atoi(const char* sp) {
   #include <LittleFS.h>
   DataStore store(LittleFS, rtc_clock);
 #elif defined(ESP32)
-  #include <SPIFFS.h>
-  DataStore store(SPIFFS, rtc_clock);
+  #include <helpers/esp32/InternalFS.h>
+  DataStore store(ESP32_FS, rtc_clock);
 #elif defined(SIM_PLATFORM)
   #include <SimFS.h>
   // Real files under ./sim_data/ (relative to the process's cwd) so
@@ -271,7 +271,7 @@ void setup() {
   #endif
     the_mesh.startInterface(serial_interface);
 #elif defined(ESP32)
-  SPIFFS.begin(true);
+  ESP32_FS.begin(true);
   store.begin();
   the_mesh.begin();
   resolveBLEPin(

examples/companion_radio/ui-lvgl/LvglPort.h

@@ -12,7 +12,7 @@
   #include <HTTPClient.h>
   #include <WiFiClientSecure.h>
   #include <Preferences.h>
-  #include <SPIFFS.h>
+  #include <helpers/esp32/InternalFS.h>
   #include <esp_heap_caps.h>
   #include <esp_system.h>
   #include <esp_core_dump.h>
@@ -262,10 +262,14 @@ static bool crashSummary(char* out, size_t n) {
 #endif
 }
 // The internal flash file system (contacts, channels, settings, trail...).
+#ifdef ESP32_LITTLEFS
+static const char* const FLASH_ROOT = "/littlefs";
+#else
 static const char* const FLASH_ROOT = "/spiffs";
+#endif
 static bool flashInfo(uint64_t& total, uint64_t& used) {
-  total = SPIFFS.totalBytes();
-  used = SPIFFS.usedBytes();
+  total = ESP32_FS.totalBytes();
+  used = ESP32_FS.usedBytes();
   return total > 0;
 }
 

solo/wio-tracker-l2/platformio.ini

@@ -70,6 +70,7 @@ build_flags =
   -D NEARBY_MAX=64
   -D HIST_ARCHIVE          ; message history also on the SD card (ui-lvgl/HistoryStore.h)
   -D GPS_SKYVIEW           ; satellites / signal / DOPs for the GPS screen (helpers/sensors/GpsSky.h)
+  -D ESP32_LITTLEFS        ; internal flash as LittleFS, not SPIFFS (helpers/esp32/InternalFS.h)
 build_src_filter = ${Wio_Tracker_L2.build_src_filter}
   +<helpers/esp32/*.cpp>
   +<helpers/ui/LGFXDisplay.cpp>
@@ -89,6 +90,7 @@ lib_deps =
   NetworkClientSecure ; 3.x name of WiFiClientSecure (the header is still there)
   Preferences
   Update              ; Settings > Firmware update
+  LittleFS
 
 ; The same firmware on the old Arduino-ESP32 2.0.17 (ESP-IDF 4.4), kept for
 ; comparison while the 3.x one settles. Not published (the name doesn't end in
@@ -106,4 +108,5 @@ lib_deps =
   HTTPClient
   WiFiClientSecure
   Preferences
+  LittleFS
 

src/helpers/esp32/InternalFS.h

@@ -0,0 +1,15 @@
+#pragma once
+
+// The ESP32's internal filesystem, on the "spiffs" partition: SPIFFS, or with
+// -D ESP32_LITTLEFS LittleFS -- far faster for the small files MeshCore keeps
+// (a settings save: ~0.5 s on SPIFFS), and safe against power loss. The two
+// formats don't mix: switching a board formats the partition on first boot.
+#ifdef ESP32_LITTLEFS
+  #include <LittleFS.h>
+  #define ESP32_FS        LittleFS
+  #define ESP32_FS_CLASS  fs::LittleFSFS
+#else
+  #include <SPIFFS.h>
+  #define ESP32_FS        SPIFFS
+  #define ESP32_FS_CLASS  fs::SPIFFSFS
+#endif