@@ -101,6 +101,7 @@ neon logo that doubles as the SVG favicon ([`7be5254`](../../commit/7be5254)):
 
 | Change | Commit |
 | --- | --- |
+| **Audiobook resume hardening**: while an audio book plays, the play-position is now checkpointed to flash every ~30 s (new **"Checkpoint audiobook position periodically"** option, on by default), so an *ungraceful* power-off (dead battery, hard power switch) only loses the last few seconds instead of falling back to the start of the track — the existing save points (track change / RFID swap / graceful shutdown) didn't cover a sudden loss of power mid-track. The learned-cards list shows each audiobook tag's saved resume point and adds a **restart-from-beginning** button (new `POST /rfidresetpos`) to clear it. i18n de/en/fr | [`PENDING4`](../../commit/PENDING4) |
 | **EQ-rule store overflow guard**: per-path EQ rules are serialized into a single NVS string capped at ~4 KB; adding too many used to silently fail. The device now rejects an over-full save with `HTTP 413` (and reports a failed NVS write as `500`), and the Files tab surfaces a clear *"EQ rule storage is full"* toast instead of losing the rule without feedback | [`PENDING5`](../../commit/PENDING5) |
 | **HTTP-sync robustness**: the file-sync manifest is now streamed straight from the network into the JSON parser (instead of buffering the whole payload in a `String` first), roughly halving peak RAM during the parse on large manifests; the cross-core sync progress message is guarded by a spinlock so the web UI can never read a half-written line | [`PENDING3`](../../commit/PENDING3) |
 | PWA support: web app manifest + app icon, "add to home screen" with proper icon and name | [`b4287b9`](../../commit/b4287b9) |
 
@@ -439,6 +439,30 @@ paths:
       responses:
         "200":
           description: Successful RFID-tag assignment deletion.
+  /rfidresetpos:
+    post:
+      tags: [Fork]
+      summary: Reset an audiobook tag's saved play-position.
+      description: >
+        Resets the saved play-position and last-played track of a tag back to the start
+        (preserving the folder/file and play mode), so a finished or abandoned audiobook
+        can be restarted from the beginning without re-assigning the card.
+      parameters:
+        - in: query
+          name: id
+          required: true
+          schema:
+            type: string
+          description: RFID tag id.
+      responses:
+        "200":
+          description: Position reset.
+        "400":
+          description: Missing id.
+        "404":
+          description: Unknown tag.
+        "409":
+          description: Tag has no play-position (NO_PLAYLIST or a modification card).
   /rfid/ids-only:
     get:
       summary: Get an array of RFID tag ID names.
 
@@ -292,6 +292,10 @@
 				"title": "Datei, Verzeichnis oder URL (^ und # als Zeichen nicht erlaubt)",
 				"placeholder": "z.B. /mp3/Hoerspiele/Yakari/Yakari_und_seine_Freunde.mp3"
 			},
+			"resume": {
+				"info": "Fortsetzen bei Titel {{track}} ({{pos}} s)",
+				"reset": "Von vorne beginnen"
+			},
 			"playmode": {
 				"title": "Abspielmodus",
 				"placeholder": "Modus auswählen",
@@ -608,6 +612,8 @@
 			"savePlayPosShutdownExp": "Beim Ausschalten der Box wird für Hörbücher die Abspielposition gespeichert. Mehr Infos <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>hier</a> unter <code>SAVE_PLAYPOS_BEFORE_SHUTDOWN</code>.",
 			"savePlayPosRfidChange": "Abspielposition bei RFID-Tag Wechsel merken",
 			"savePlayPosRfidChangeExp": "Beim Wechsel zu einem neuen RFID-Tag wird für Hörbücher die Abspielposition gespeichert. Betrifft keine Modifikations-Tags. Mehr Infos <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>hier</a> unter <code>SAVE_PLAYPOS_WHEN_RFID_CHANGE</code>.",
+			"savePlayPosPeriodic": "Hörbuch-Position regelmäßig sichern",
+			"savePlayPosPeriodicExp": "Während ein Hörbuch läuft, wird die Position alle ~30 s im Flash gesichert. So gehen bei einem unerwarteten Stromausfall (leerer Akku, harter Aus-Schalter) nur die letzten Sekunden verloren statt bis zum Anfang des Tracks zurückzuspringen. Fork-Funktion.",
 			"pauseIfRfidRemoved": "Pause wenn RFID-Tag entfernt",
 			"pauseIfRfidRemovedExp": "Pausieren wenn RFID-Tag entfernt wird. Mehr Infos <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>hier</a> unter <code>PAUSE_WHEN_RFID_REMOVED</code>.",
 			"dontAcceptRfidTwice": "Denselben RFID-Tag nicht erneut akzeptieren",
 
@@ -292,6 +292,10 @@
 				"title": "File, directory or URL (^ and # aren't allowed as chars)",
 				"placeholder": "f.e. /mp3/Audiobook/Yakari/Yakari_and_Friends.mp3"
 			},
+			"resume": {
+				"info": "Resume at track {{track}} ({{pos}} s)",
+				"reset": "Restart from the beginning"
+			},
 			"playmode": {
 				"title": "Playmode",
 				"placeholder": "Select mode",
@@ -608,6 +612,8 @@
 			"savePlayPosShutdownExp": "When the box is switched off, the playback position for audio books is saved. More information <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>here</a> under <code>SAVE_PLAYPOS_BEFORE_SHUTDOWN</code>.",
 			"savePlayPosRfidChange": "Remember playback position at RFID tag change",
 			"savePlayPosRfidChangeExp": "When switching to a new RFID tag, the playback position is saved for audio books. Does not affect modification tags. More information <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>here</a> under <code>SAVE_PLAYPOS_WHEN_RFID_CHANGE</code>.",
+			"savePlayPosPeriodic": "Checkpoint audiobook position periodically",
+			"savePlayPosPeriodicExp": "While an audio book plays, the position is saved to flash every ~30 s. This way an unexpected power loss (dead battery, hard power-off) only loses the last few seconds instead of falling back to the start of the track. Fork feature.",
 			"pauseIfRfidRemoved": "Pause when RFID tag is removed",
 			"pauseIfRfidRemovedExp": "Playback is paused when the RFID tag is removed. More information <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>here</a> under <code>PAUSE_IF_RFID_REMOVED</code>.",
 			"dontAcceptRfidTwice": "Don't accept the same RFID twice",
 
@@ -285,6 +285,10 @@
 				"title": "Fichier, répertoire ou URL (^ et # ne sont pas autorisés comme caractères)",
 				"placeholder": "par exemple /mp3/Audiobook/Yakari/Yakari_and_Friends.mp3"
 			},
+			"resume": {
+				"info": "Reprendre à la piste {{track}} ({{pos}} s)",
+				"reset": "Recommencer depuis le début"
+			},
 			"playmode": {
 				"title": "Mode de lecture",
 				"placeholder": "Sélectionnez le mode",
@@ -597,6 +601,8 @@
 			"savePlayPosShutdownExp": "Lorsque la boîte est éteinte, la position de lecture est enregistrée pour les livres audio. Plus d'informations <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>ici</a> sous <code>SAVE_PLAYPOS_BEFORE_SHUTDOWN</code>.",
 			"savePlayPosRfidChange": "Mémoriser la position de lecture au changement de tag RFID",
 			"savePlayPosRfidChangeExp": "Lors du passage à une nouvelle balise RFID, la position de lecture est enregistrée pour les livres audio. Plus d'informations <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>ici</a> sous <code>SAVE_PLAYPOS_WHEN_RFID_CHANGE</code>.",
+			"savePlayPosPeriodic": "Sauvegarder régulièrement la position du livre audio",
+			"savePlayPosPeriodicExp": "Pendant la lecture d'un livre audio, la position est enregistrée dans la mémoire flash toutes les ~30 s. Ainsi, une coupure de courant inattendue (batterie vide, arrêt brutal) ne perd que les dernières secondes au lieu de revenir au début de la piste. Fonction du fork.",
 			"pauseIfRfidRemoved": "Mettre en pause si la balise RFID est retirée",
 			"pauseIfRfidRemovedExp": "Mettre en pause la lecture si la balise RFID est retirée. Plus d'informations <a href='https://forum.espuino.de/t/welche-optionen-beim-kompilieren-gibt-es/120' target='_blank'>ici</a> sous <code>PAUSE_IF_RFID_REMOVED</code>.",
 			"dontAcceptRfidTwice": "Ne pas accepter la balise RFID deux fois",
 
@@ -2245,6 +2245,15 @@ <h5 class="modal-title" data-i18n="tools.nvs.erase.title"></h5>
 									data-i18n="[data-bs-content]general.options.savePlayPosRfidChangeExp"
 									tabindex="0"><i class="fas fa-circle-question"></i></a>
 							</div>
+							<div class="col-12 col-md-6 d-flex gap-2 align-items-center mb-1">
+								<input type="checkbox" id="savePlayPosPeriodic" name="savePlayPosPeriodic"
+									value="false">
+								<label for="savePlayPosPeriodic"
+									data-i18n="general.options.savePlayPosPeriodic"></label>
+								<a href="#" class="link-secondary" data-bs-toggle="popover"
+									data-i18n="[data-bs-content]general.options.savePlayPosPeriodicExp"
+									tabindex="0"><i class="fas fa-circle-question"></i></a>
+							</div>
 							<div class="col-12 col-md-6 d-flex gap-2 align-items-center mb-1">
 								<input type="checkbox" id="playLastRfidOnReboot" name="playLastRfidOnReboot"
 									value="false">
@@ -4757,6 +4766,7 @@ <h5 class="modal-title" data-i18n="tools.nvs.erase.title"></h5>
 				$('#playMono').prop('checked', genSettings.playMono);
 				$('#savePlayPosShutdown').prop('checked', genSettings.savePosShutdown);
 				$('#savePlayPosRfidChange').prop('checked', genSettings.savePosRfidChge);
+				$('#savePlayPosPeriodic').prop('checked', genSettings.savePosPeriodic);
 				$('#playLastRfidOnReboot').prop('checked', genSettings.playLastRfidOnReboot);
 				$('#pauseIfRfidRemoved').prop('checked', genSettings.pauseIfRfidRemoved);
 				$('#dontAcceptRfidTwice').prop('checked', genSettings.dontAcceptRfidTwice);
@@ -5110,9 +5120,27 @@ <h5 class="modal-title" data-i18n="tools.nvs.erase.title"></h5>
 					rfidElem.appendChild(document.createElement("br"));
 					rfidElem.appendChild(document.createTextNode(rfid.fileOrUrl));
 				}
+				// audiobook modes (AUDIOBOOK / _LOOP / _RECURSIVE) can carry a saved play-position
+				var isAudiobook = (rfid.playMode === 3 || rfid.playMode === 4 || rfid.playMode === 16);
+				var hasProgress = isAudiobook && (((rfid.lastPlayPos || 0) > 0) || ((rfid.trackLastPlayed || 0) > 0));
+				if (hasProgress) {
+					rfidElem.appendChild(document.createElement("br"));
+					let resumeInfo = document.createElement("small");
+					resumeInfo.classList.add("text-info");
+					resumeInfo.textContent = i18next.t("files.rfid.resume.info", { track: (rfid.trackLastPlayed || 0) + 1, pos: rfid.lastPlayPos || 0 });
+					rfidElem.appendChild(resumeInfo);
+				}
 				let deleteSpan = document.createElement("span");
 				deleteSpan.classList.add("float-end");
 				deleteSpan.classList.add("button-group");
+				if (hasProgress) {
+					// reset the saved play-position so the book restarts from the beginning
+					let resetButton = document.createElement("button");
+					resetButton.classList.add("btn", "btn-secondary", "fa", "fa-backward-step", "me-1");
+					resetButton.setAttribute("title", i18next.t("files.rfid.resume.reset"));
+					resetButton.addEventListener("click", function () { resetRfidPos(rfid.id); });
+					deleteSpan.appendChild(resetButton);
+				}
 				let deleteButton = document.createElement("button");
 				deleteButton.classList.add("btn");
 				deleteButton.classList.add("btn-danger");
@@ -5129,6 +5157,16 @@ <h5 class="modal-title" data-i18n="tools.nvs.erase.title"></h5>
 			document.getElementById('eraseNvs').setAttribute('data-visible', (rfidList.length > 0));
 			document.getElementById('exportNvs').setAttribute('data-visible', (rfidList.length > 0));
 		}
+		// reset an audiobook tag's saved play-position back to the start (POST /rfidresetpos)
+		async function resetRfidPos(tagId) {
+			var response = await fetch("http://" + host + "/rfidresetpos?id=" + encodeURIComponent(tagId), { method: "POST" });
+			if (response.ok) {
+				flashActionOk();
+				rebuildRFIDList();
+			} else {
+				toaster.error(response.statusText);
+			}
+		}
 		async function deleteRFID(tagId) {
 			console.log("deleting", tagId);
 			$('#deleteRFIDModal').modal('hide');
@@ -5299,6 +5337,7 @@ <h5 class="modal-title" data-i18n="tools.nvs.erase.title"></h5>
 					playMono: $('#playMono').prop('checked'),
 					savePosShutdown: $('#savePlayPosShutdown').prop('checked'),
 					savePosRfidChge: $('#savePlayPosRfidChange').prop('checked'),
+					savePosPeriodic: $('#savePlayPosPeriodic').prop('checked'),
 					playLastRfidOnReboot: $('#playLastRfidOnReboot').prop('checked'),
 					pauseIfRfidRemoved: $('#pauseIfRfidRemoved').prop('checked'),
 					dontAcceptRfidTwice: $('#dontAcceptRfidTwice').prop('checked'),
 
@@ -298,6 +298,14 @@ float Audio_GetVolume(float t) {
 	return val1 + (val2 - val1) * fraction;
 }
 
+// When true, the audiobook play-position is checkpointed to NVS periodically while playing
+// (see AudioPlayer_Cyclic). Mirrors the "savePosPeriodic" web setting; default on.
+static bool gSavePosPeriodic = true;
+
+void AudioPlayer_SetSavePosPeriodic(bool enabled) {
+	gSavePosPeriodic = enabled;
+}
+
 void AudioPlayer_Init(void) {
 	// create audio object
 	audio = new AudioCustom();
@@ -378,6 +386,7 @@ void AudioPlayer_Init(void) {
 	AudioPlayer_StationLogoUrl = "";
 	gPlayProperties.playlist = allocatePlaylist();
 	gPlayProperties.SavePlayPosRfidChange = gPrefsSettings.getBool("savePosRfidChge", false); // SAVE_PLAYPOS_WHEN_RFID_CHANGE
+	gSavePosPeriodic = gPrefsSettings.getBool("savePosPeriodic", true); // periodic audiobook play-position checkpoint
 	gPlayProperties.pauseOnMinVolume = gPrefsSettings.getBool("pauseOnMinVol", false); // PAUSE_ON_MIN_VOLUME
 #ifdef PAUSE_WHEN_RFID_REMOVED
 	gPlayProperties.pauseIfRfidRemoved = gPrefsSettings.getBool("pauseRfidRem", true);
@@ -440,6 +449,13 @@ void AudioPlayer_Exit(void) {
 
 static uint32_t lastPlayingTimestamp = 0;
 
+// Periodically persist the audiobook play-position to NVS while playing, so an *ungraceful*
+// power-off (dead battery, hard power switch) doesn't lose the whole book back to the last
+// track boundary. The existing save points (track change / RFID swap / graceful shutdown)
+// don't cover a sudden loss of power mid-track. Throttled so NVS wear stays negligible.
+static constexpr uint32_t SAVE_POS_CHECKPOINT_INTERVAL_MS = 30000;
+static uint32_t lastPosCheckpointMs = 0;
+
 void AudioPlayer_Cyclic(void) {
 	if (AudioPlayer_UploadActive) {
 		return;
@@ -451,6 +467,15 @@ void AudioPlayer_Cyclic(void) {
 		lastPlayingTimestamp = millis();
 		playTimeSecSinceStart += 1;
 		Playstats_AddSecond(); // accumulate per-day listening-time statistics
+
+		// periodic audiobook play-position checkpoint (see note above). saveLastPlayPosition
+		// is only set for the position-saving audiobook modes, so this is a no-op otherwise.
+		if (gSavePosPeriodic && gPlayProperties.saveLastPlayPosition && gPlayProperties.playlist != nullptr && audio && audio->isRunning()) {
+			if (millis() - lastPosCheckpointMs >= SAVE_POS_CHECKPOINT_INTERVAL_MS) {
+				lastPosCheckpointMs = millis();
+				AudioPlayer_NvsRfidWriteWrapper(gPlayProperties.playRfidTag, audio->getAudioCurrentTime(), gPlayProperties.playMode, gPlayProperties.currentTrackNumber);
+			}
+		}
 	}
 
 	// Actual loop stuff
@@ -1678,6 +1703,12 @@ size_t AudioPlayer_NvsRfidWriteWrapper(const char *_rfidCardId, const uint32_t _
 	gPrefsRfid.putString("212130160042", "#/mp3/Hoerspiele/Yakari/Sammlung2#0#3#0");*/
 }
 
+// Resets a tag's saved play-position and last-played track to the start, keeping the
+// folder/file and play mode intact (so an audiobook can be restarted from the beginning).
+void AudioPlayer_ResetRfidPos(const char *_rfidCardId, const uint8_t _playMode) {
+	AudioPlayer_NvsRfidWriteWrapper(_rfidCardId, 0, _playMode, 0);
+}
+
 // Adds webstream to playlist; same like SdCard_ReturnPlaylist() but always only one entry
 std::optional<Playlist *> AudioPlayer_ReturnPlaylistFromWebstream(const char *_webUrl) {
 	Playlist *playlist = allocatePlaylist();
 
@@ -65,6 +65,7 @@ void AudioPlayer_NotifyUploadEnd(void);
 
 void AudioPlayer_Init(void);
 void AudioPlayer_Exit(void);
+void AudioPlayer_SetSavePosPeriodic(bool enabled);
 void AudioPlayer_Cyclic(void);
 void AudioPlayer_Loop(void);
 uint8_t AudioPlayer_GetRepeatMode(void);
@@ -76,6 +77,8 @@ String AudioPlayer_GetEqualizerProfile(void);
 void AudioPlayer_ReloadEqRules(void);
 void AudioPlayer_ApplyEqualizerForPath(const char *trackPath);
 void AudioPlayer_SetPlaylist(const char *_itemToPlay, const uint32_t _lastPlayPos, const uint32_t _playMode, const uint16_t _trackLastPlayed);
+// Resets a tag's saved play-position + last-played track to the start (preserving folder/mode).
+void AudioPlayer_ResetRfidPos(const char *_rfidCardId, const uint8_t _playMode);
 void AudioPlayer_SetTrackControl(const uint8_t trackCommand);
 void AudioPlayer_PauseOnMinVolume(const uint8_t oldVolume, const uint8_t newVolume);
 void AudioPlayer_PlayReadyMsg(void);