diff --git a/get-started/csi_recv_router/main/app_main.c b/get-started/csi_recv_router/main/app_main.c
index 926a6d0..c245716 100644
--- a/get-started/csi_recv_router/main/app_main.c
+++ b/get-started/csi_recv_router/main/app_main.c
@@ -1296,7 +1296,10 @@ void app_main()
 
     udp_socket_init();
     wifi_csi_init();
+#if !CONFIG_IDF_TARGET_ESP32
+    /* Promiscuous mode disables CSI on original ESP32 — only enable on newer chips */
     wifi_promiscuous_init();
+#endif
     wifi_ping_router_start();
 
     xTaskCreate(cmd_task, "cmd_task", 4096, NULL, 5, NULL);