diff --git a/src/chat/chat_core.c b/src/chat/chat_core.c
index 31d97b86..1dc1ed59 100644
--- a/src/chat/chat_core.c
+++ b/src/chat/chat_core.c
@@ -107,6 +107,11 @@ int chat_core_init(struct UTUN_INSTANCE* inst, const char* db_path) {
         if (!cc->shared_db) sqlite3_close(cc->db);
         inst->chat_core = NULL; u_free(cc); return -1;
     }
+    if (strlen(db_path) >= sizeof(cc->db_path) || media_index_init(cc->db)) {
+        DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "chat media schema/path initialization failed");
+        if (!cc->shared_db) sqlite3_close(cc->db);
+        inst->chat_core = NULL; u_free(cc); return -1;
+    }
     cc->inst       = inst;
     cc->my_node_id = inst->node_id;
 
@@ -141,9 +146,6 @@ int chat_core_init(struct UTUN_INSTANCE* inst, const char* db_path) {
     /* register adm_tags change callback → CHAT_EVT_MEMBER_UPDATED */
     chat_member_init(inst);
 
-    /* create media_files table */
-    media_index_init(cc->db);
-
     db_exec(cc,
         "CREATE TABLE IF NOT EXISTS local_identity ("
         "  id              INTEGER PRIMARY KEY CHECK (id = 1),"
@@ -172,13 +174,11 @@ int chat_core_init(struct UTUN_INSTANCE* inst, const char* db_path) {
     );
     /* store media_base for block_req handler */
     {
-        char mbase[512];
+        char mbase[MEDIA_BASE_MAX];
         const char* ls = strrchr(db_path, '/');
-        if (ls) snprintf(mbase, sizeof(mbase), "%.*s", (int)(ls - db_path), db_path);
-        else snprintf(mbase, sizeof(mbase), "%s", db_path);
-        char sql[1024]; snprintf(sql, sizeof(sql),
-            "INSERT OR REPLACE INTO ui_state(key,value) VALUES('media_base','%s')", mbase);
-        sqlite3_exec(cc->db, sql, NULL, NULL, NULL);
+        if (ls) snprintf(mbase, sizeof(mbase), "%.*s", ls == db_path ? 1 : (int)(ls - db_path), db_path);
+        else snprintf(mbase, sizeof(mbase), ".");
+        if (media_index_set_base(cc->db, mbase)) { chat_core_destroy(inst); return -1; }
         DEBUG_INFO(DEBUG_CATEGORY_CHAT_SYNC, "%s: media_base=%s", CC_ID, mbase);
     }
 
diff --git a/src/media_delivery/media_download.c b/src/media_delivery/media_download.c
index df0896a0..857a3d72 100644
--- a/src/media_delivery/media_download.c
+++ b/src/media_delivery/media_download.c
@@ -639,30 +639,19 @@ void media_download_handle_chunk(struct UTUN_INSTANCE* inst,
 
 /* Регистрирует скачанные блоки в media_files (location = собранный файл), чтобы узел
  * мог отдавать их как держатель. Вызывается после успешной сборки и проверки хеша. */
-static void md_dl_register_servable(struct media_download* dl) {
+static int md_dl_register_servable(struct media_download* dl) {
     struct UTUN_INSTANCE* inst = dl->inst;
     sqlite3* db = inst ? inst->topo_sqlite_db : NULL;
-    if (!db) { DEBUG_WARN(DEBUG_CATEGORY_GENERAL, "%s: register_servable — no DB", MDL_ID); return; }
-
-    char chat_id[32];
-    snprintf(chat_id, sizeof(chat_id), "%llu", (unsigned long long)dl->group_id);
-
-    /* location = dest_path относительно media_base (как в media_index_commit) */
-    const char* rel = dl->dest_path;
-    size_t base_len = strlen(dl->media_base);
-    if (strncmp(rel, dl->media_base, base_len) == 0 && rel[base_len] == '/')
-        rel += base_len + 1;
-
-    for (int n = 0; n < dl->num_blocks; n++) {
-        if (media_index_register_downloaded(db, dl->media_id, dl->blocks[n].block_id,
-                                            dl->content_hash, chat_id, rel, inst->node_id,
-                                            dl->file_size, dl->blocks[n].expected_size, n,
-                                            (int64_t)n * dl->block_size) != 0) {
-            DEBUG_ERROR(DEBUG_CATEGORY_GENERAL, "%s: register_servable failed blk=%d", MDL_ID, n);
-        }
-    }
-    DEBUG_INFO(DEBUG_CATEGORY_MEDIA, "%s: registered %d downloaded blocks as servable (%s)",
-               MDL_ID, dl->num_blocks, rel);
+    if (!db) { DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: register_servable without DB", MDL_ID); return -1; }
+    char chat_id[32]; snprintf(chat_id, sizeof(chat_id), "%llu", (unsigned long long)dl->group_id);
+    uint8_t* ids = u_malloc((uint32_t)dl->num_blocks * 16);
+    if (!ids) { DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: register_servable allocation failed", MDL_ID); return -1; }
+    for (int n = 0; n < dl->num_blocks; n++) memcpy(ids + (size_t)n * 16, dl->blocks[n].block_id, 16);
+    struct media_index_result result = { .file_size = dl->file_size, .block_size = dl->block_size,
+        .num_blocks = dl->num_blocks, .block_ids = ids };
+    memcpy(result.media_id, dl->media_id, 16); memcpy(result.content_hash, dl->content_hash, 32);
+    int rc = media_index_register_downloaded_file(db, &result, inst->node_id, chat_id, dl->dest_path, dl->media_base);
+    u_free(ids); return rc;
 }
 
 void media_download_handle_done(struct UTUN_INSTANCE* inst,
@@ -783,8 +772,8 @@ void media_download_handle_done(struct UTUN_INSTANCE* inst,
         } }
         dl->assembled = 1;
         DEBUG_INFO(DEBUG_CATEGORY_GENERAL, "%s: file assembled: %s", MDL_ID, dl->dest_path);
-        md_dl_register_servable(dl);
-        md_dl_finish(dl, 0);
+        int registered = md_dl_register_servable(dl);
+        md_dl_finish(dl, registered);
         return;
     }
 
@@ -877,6 +866,15 @@ int media_download_start(struct UTUN_INSTANCE* inst, uint64_t group_id,
     struct media_delivery_ctx* md = &inst->md;
     if (!md->initialized) { DEBUG_ERROR(DEBUG_CATEGORY_GENERAL, "%s: start before media_delivery init", MDL_ID); return -1; }
 
+    char location[MEDIA_PATH_MAX];
+    if (result->file_size <= 0 || result->block_size <= 0 || result->block_size > UINT32_MAX
+        || result->num_blocks <= 0 || (uint64_t)result->num_blocks > UINT32_MAX / 64
+        || (result->file_size - 1) / result->block_size + 1 != result->num_blocks
+        || !result->block_ids || !result->block_sigs || media_index_location(dest_path, media_base, location)
+        || media_index_set_base(inst->topo_sqlite_db, media_base)) {
+        DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "%s: invalid file geometry/path/base before download", MDL_ID); return -1;
+    }
+
     /* дедуп: та же медиа уже качается */
     if (md_dl_find(inst, result->media_id)) {
         DEBUG_WARN(DEBUG_CATEGORY_GENERAL, "%s: DUPLICATE download media=%02x%02x... ignored", MDL_ID, result->media_id[0], result->media_id[1]);
@@ -933,15 +931,6 @@ int media_download_start(struct UTUN_INSTANCE* inst, uint64_t group_id,
 
     dl = (struct media_download*)qe->data;
 
-    /* сохраняем media_base в ui_state — чтобы после скачивания узел мог отдавать блоки
-       (md_handle_block_req открывает файл по ui_state.media_base + location) */
-    {
-        sqlite3_exec(inst->topo_sqlite_db, "CREATE TABLE IF NOT EXISTS ui_state(key TEXT PRIMARY KEY, value TEXT)", NULL, NULL, NULL);
-        sqlite3_stmt* us = NULL;
-        sqlite3_prepare_v2(inst->topo_sqlite_db, "INSERT OR REPLACE INTO ui_state(key,value) VALUES('media_base',?)", -1, &us, NULL);
-        if (us) { sqlite3_bind_text(us, 1, media_base, -1, SQLITE_STATIC); sqlite3_step(us); sqlite3_finalize(us); }
-    }
-
     md_dl_collect_supernodes(inst, dl);
     dl->last_activity_tb = get_time_tb();
     dl->watchdog_timer = uasync_set_timeout(inst->ua, (int)md_dl_stall_tb(inst), dl, md_dl_watchdog_cb, "md_dl_wd");