diff --git a/src/chat/chat_feedback.c b/src/chat/chat_feedback.c
index 2c414bae..283e7edd 100644
--- a/src/chat/chat_feedback.c
+++ b/src/chat/chat_feedback.c
@@ -171,12 +171,19 @@ int chat_feedback_get(struct UTUN_INSTANCE* inst, const char* channel, const uin
     snprintf(sql, sizeof(sql), "SELECT message_id,node_id,kind,ver,data,signature FROM %s"
         " WHERE message_id=? AND node_id=? AND kind=?", table);
     sqlite3_stmt* st = NULL;
-    if (sqlite3_prepare_v2(inst->topo_sqlite_db, sql, -1, &st, NULL) != SQLITE_OK) return fb_db_error(inst, channel, "get");
-    sqlite3_bind_blob(st, 1, message_id, 32, SQLITE_STATIC); sqlite3_bind_int64(st, 2, (sqlite3_int64)node_id);
-    sqlite3_bind_int(st, 3, kind);
-    int rc = sqlite3_step(st), result = rc == SQLITE_ROW ? (fb_read_row(st, out) < 0 ? -1 : 1) : 0;
-    sqlite3_finalize(st);
-    if (rc != SQLITE_ROW && rc != SQLITE_DONE) return fb_db_error(inst, channel, "get step");
+    int rc = sqlite3_prepare_v2(inst->topo_sqlite_db, sql, -1, &st, NULL);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_blob(st, 1, message_id, 32, SQLITE_STATIC);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_int64(st, 2, (sqlite3_int64)node_id);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_int(st, 3, kind);
+    if (rc == SQLITE_OK) rc = sqlite3_step(st);
+    struct chat_feedback_record record;
+    int result = rc == SQLITE_ROW ? (fb_read_row(st, &record) < 0 ? -1 : 1) : 0;
+    int final = sqlite3_finalize(st);
+    if ((rc != SQLITE_ROW && rc != SQLITE_DONE) || final != SQLITE_OK) {
+        DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "feedback: lookup failed ch=%s node=%016llx kind=%u step=%d finalize=%d db=%s",
+            channel, (unsigned long long)node_id, kind, rc, final, sqlite3_errmsg(inst->topo_sqlite_db)); return -1;
+    }
+    if (result > 0) *out = record;
     return result;
 }
 
@@ -217,14 +224,22 @@ static int fb_apply_row(struct UTUN_INSTANCE* inst, const char* channel, const s
     snprintf(sql, sizeof(sql), "INSERT INTO %s(record_key,bucket,message_id,node_id,kind,ver,data,signature)"
         " VALUES(?,?,?,?,?,?,?,?) ON CONFLICT(record_key) DO UPDATE SET ver=excluded.ver,data=excluded.data,signature=excluded.signature", table);
     sqlite3_stmt* st = NULL;
-    if (sqlite3_prepare_v2(inst->topo_sqlite_db, sql, -1, &st, NULL) != SQLITE_OK) return fb_db_error(inst, channel, "put");
-    sqlite3_bind_blob(st, 1, record_key.bytes, 32, SQLITE_STATIC);
-    sqlite3_bind_int64(st, 2, (sqlite3_int64)(fb_read64(record_key.bytes) >> 39));
-    sqlite3_bind_blob(st, 3, r->message_id, 32, SQLITE_STATIC); sqlite3_bind_int64(st, 4, (sqlite3_int64)r->node_id);
-    sqlite3_bind_int(st, 5, r->kind); sqlite3_bind_int64(st, 6, (sqlite3_int64)r->ver);
-    sqlite3_bind_blob(st, 7, r->data, r->data_len, SQLITE_STATIC); sqlite3_bind_blob(st, 8, r->signature, 64, SQLITE_STATIC);
-    int rc = sqlite3_step(st); sqlite3_finalize(st);
-    if (rc != SQLITE_DONE) return fb_db_error(inst, channel, "put step");
+    int rc = sqlite3_prepare_v2(inst->topo_sqlite_db, sql, -1, &st, NULL);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_blob(st, 1, record_key.bytes, 32, SQLITE_STATIC);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_int64(st, 2, (sqlite3_int64)(fb_read64(record_key.bytes) >> 39));
+    if (rc == SQLITE_OK) rc = sqlite3_bind_blob(st, 3, r->message_id, 32, SQLITE_STATIC);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_int64(st, 4, (sqlite3_int64)r->node_id);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_int(st, 5, r->kind);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_int64(st, 6, (sqlite3_int64)r->ver);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_blob(st, 7, r->data, r->data_len, SQLITE_STATIC);
+    if (rc == SQLITE_OK) rc = sqlite3_bind_blob(st, 8, r->signature, 64, SQLITE_STATIC);
+    if (rc == SQLITE_OK) rc = sqlite3_step(st);
+    int changed = rc == SQLITE_DONE ? sqlite3_changes(inst->topo_sqlite_db) : 0;
+    int final = sqlite3_finalize(st);
+    if (rc != SQLITE_DONE || changed != 1 || final != SQLITE_OK) {
+        DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "feedback: write failed ch=%s node=%016llx kind=%u step=%d changes=%d finalize=%d db=%s",
+            channel, (unsigned long long)r->node_id, r->kind, rc, changed, final, sqlite3_errmsg(inst->topo_sqlite_db)); return -1;
+    }
     if (merkle_sync_recompute_path(inst, MT_DATA_FEEDBACK, channel, fb_read64(record_key.bytes)) < 0) return -1;
     DEBUG_DEBUG(DEBUG_CATEGORY_CHAT_SYNC, "feedback: applied ch=%s message=%s node=%016llx kind=%u ver=%llu previous=%llu bytes=%u",
         channel, message_hex, (unsigned long long)r->node_id, r->kind, (unsigned long long)r->ver,
@@ -239,15 +254,19 @@ static void fb_committed(struct UTUN_INSTANCE* inst, const char* channel, const
     chat_event_post(inst, CHAT_EVT_FEEDBACK_CHANGED, event, (int)len + 34);
 }
 
-/* Завершает savepoint, при ошибке не публикует частичные изменения. */
+/* Завершает только свою транзакцию; неудачный rollback никогда не переходит в commit. */
 static int fb_finish_transaction(struct UTUN_INSTANCE* inst, const char* channel, int result) {
     sqlite3* db = inst->topo_sqlite_db;
-    if (result < 0 && sqlite3_exec(db, "ROLLBACK TO feedback_update", NULL, NULL, NULL) != SQLITE_OK)
+    if (result >= 0) {
+        if (sqlite3_exec(db, "COMMIT /* feedback update */", NULL, NULL, NULL) == SQLITE_OK) return result;
+        fb_db_error(inst, channel, "commit");
+    }
+    if (!sqlite3_get_autocommit(db) && sqlite3_exec(db, "ROLLBACK", NULL, NULL, NULL) != SQLITE_OK)
         fb_db_error(inst, channel, "rollback");
-    if (sqlite3_exec(db, "RELEASE feedback_update", NULL, NULL, NULL) == SQLITE_OK) return result;
-    fb_db_error(inst, channel, "commit");
-    if (sqlite3_exec(db, "ROLLBACK TO feedback_update; RELEASE feedback_update", NULL, NULL, NULL) != SQLITE_OK)
-        fb_db_error(inst, channel, "commit cleanup");
+    if (!sqlite3_get_autocommit(db)) {
+        DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "feedback: transaction remains open ch=%s; owner must stop core and close DB after callback", channel);
+        utun_instance_stop(inst);
+    }
     return -1;
 }
 
@@ -259,7 +278,7 @@ int chat_feedback_apply(struct UTUN_INSTANCE* inst, const char* channel, const s
     if (!sqlite3_get_autocommit(inst->topo_sqlite_db)) {
         DEBUG_ERROR(DEBUG_CATEGORY_CHAT_SYNC, "feedback: public apply inside external transaction ch=%s", channel); return -1;
     }
-    if (sqlite3_exec(inst->topo_sqlite_db, "SAVEPOINT feedback_update", NULL, NULL, NULL) != SQLITE_OK)
+    if (sqlite3_exec(inst->topo_sqlite_db, "BEGIN IMMEDIATE /* feedback update */", NULL, NULL, NULL) != SQLITE_OK)
         return fb_db_error(inst, channel, "begin");
     int result = fb_finish_transaction(inst, channel, fb_apply_row(inst, channel, r));
     if (result > 0) { merkle_sync_changed(inst, MT_DATA_FEEDBACK, channel); fb_committed(inst, channel, r); }