diff --git a/tools/chatgui-android/libutun_lite/instance_lite.c b/tools/chatgui-android/libutun_lite/instance_lite.c
index b12b0cc6..58204761 100644
--- a/tools/chatgui-android/libutun_lite/instance_lite.c
+++ b/tools/chatgui-android/libutun_lite/instance_lite.c
@@ -298,7 +298,7 @@ static void* instance_thread(void* arg) {
     IL_LOGI("instance created, node_id=0x%016llx", (unsigned long long)g_inst->node_id);
 
     /* Core owns SQLite and transport; this frontend starts only the chat service. */
-    if (utun_core_start(g_inst) != 0 || chat_service_start(g_inst) != 0) {
+    if (utun_core_start(g_inst) != 0 || chat_service_start(g_inst) != 0 || android_stream_attach(g_inst) < 0) {
         IL_LOGE("core/chat start failed");
         utun_instance_destroy(g_inst);
         g_inst = NULL;
@@ -312,7 +312,6 @@ static void* instance_thread(void* arg) {
         return NULL;
     }
 
-    android_stream_attach(g_inst);
     /* sockets are now created — sync my addresses to DB */
     chat_core_sync_my_addresses(g_inst);
     fire_local_sockets_event();
@@ -389,8 +388,9 @@ static void* instance_thread(void* arg) {
         chat_event_set_handler(g_inst, chat_event_forward);
 
         /* Recreate core and chat independently of UTUN. */
-        if (utun_core_start(g_inst) != 0 || chat_service_start(g_inst) != 0) { IL_LOGE("poll exit: core/chat start failed"); break; }
-        android_stream_attach(g_inst);
+        if (utun_core_start(g_inst) != 0 || chat_service_start(g_inst) != 0 || android_stream_attach(g_inst) < 0) {
+            IL_LOGE("poll exit: core/chat/stream bridge start failed"); break;
+        }
         chat_core_sync_my_addresses(g_inst);
         fire_local_sockets_event();
         if (g_inst->config->global.name[0]) chat_core_update_my_name(g_inst, g_inst->config->global.name);
diff --git a/tools/chatgui-android/libutun_lite/stream_bridge.c b/tools/chatgui-android/libutun_lite/stream_bridge.c
index b102d7c6..ea184aee 100644
--- a/tools/chatgui-android/libutun_lite/stream_bridge.c
+++ b/tools/chatgui-android/libutun_lite/stream_bridge.c
@@ -303,11 +303,16 @@ static void media_process(void *arg) {
 }
 
 /* Attach/detach — обязательная граница lifetime ядра. */
-void android_stream_attach(struct UTUN_INSTANCE *inst) {
+int android_stream_attach(struct UTUN_INSTANCE *inst) {
     pthread_mutex_lock(&media_lock);
+    if (!inst || !inst->stream || (media_inst && media_inst != inst)) {
+        DEBUG_ERROR(DEBUG_CATEGORY_STREAM, "Android stream attach rejected inst=%p owner=%p", (void *)inst, (void *)media_inst);
+        pthread_mutex_unlock(&media_lock); return -1;
+    }
     media_inst = inst; stream_set_event_callback(inst, media_event, NULL);
     DEBUG_INFO(DEBUG_CATEGORY_STREAM, "Android stream bridge attached");
     pthread_mutex_unlock(&media_lock);
+    return 0;
 }
 void android_stream_detach(struct UTUN_INSTANCE *inst) {
     pthread_mutex_lock(&media_lock);
@@ -352,7 +357,11 @@ int android_stream_feed(uint64_t id, int video, uint64_t pts, int key, const uin
     }
     pthread_mutex_lock(&media_lock);
     int result = -1, track = video ? 0 : 1;
-    if (!media_inst || publisher.id != id || publisher.stopping || publisher.finished) goto done;
+    if (!media_inst || publisher.id != id || publisher.stopping || publisher.finished) {
+        DEBUG_WARN(DEBUG_CATEGORY_STREAM, "Android stream feed rejected id=%llu owner=%llu attached=%d stopping=%d finished=%d",
+                   (unsigned long long)id, (unsigned long long)publisher.id, media_inst != NULL, publisher.stopping, publisher.finished);
+        goto done;
+    }
     if ((!video && !publisher.format.audio_codec) || (publisher.seen[track] && pts <= publisher.last_pts[track])) {
         DEBUG_ERROR(DEBUG_CATEGORY_STREAM, "Android stream feed invalid track/PTS id=%llu pts=%llu",
                     (unsigned long long)id, (unsigned long long)pts); goto done;
diff --git a/tools/chatgui-android/libutun_lite/stream_bridge.h b/tools/chatgui-android/libutun_lite/stream_bridge.h
index 646fa8c0..fbbcaa00 100644
--- a/tools/chatgui-android/libutun_lite/stream_bridge.h
+++ b/tools/chatgui-android/libutun_lite/stream_bridge.h
@@ -12,7 +12,8 @@
 #include <stdint.h>
 
 struct UTUN_INSTANCE;
-void android_stream_attach(struct UTUN_INSTANCE *inst);
+/* 0 attached, -1 invalid/busy: нельзя передать singleton другому ядру до detach старого. */
+int android_stream_attach(struct UTUN_INSTANCE *inst);
 void android_stream_detach(struct UTUN_INSTANCE *inst);
 int android_stream_open(uint64_t id, uint64_t group, uint64_t source, unsigned width, unsigned height,
                         unsigned rotation, int audio);