diff --git a/firmware/esp32-csi-node/main/csi_collector.c b/firmware/esp32-csi-node/main/csi_collector.c
index 484b40cc..56ae21f7 100644
--- a/firmware/esp32-csi-node/main/csi_collector.c
+++ b/firmware/esp32-csi-node/main/csi_collector.c
@@ -637,6 +637,23 @@ static void hop_timer_cb(void *arg)
     csi_hop_next_channel();
 }
 
+void csi_collector_enable_data_capture(void)
+{
+    /* MGMT-only (RuView#396) starves the CSI callback on display-less boards
+     * (RuView#521/#893): beacons alone are sparse, yield collapses to 0 pps.
+     * Without a display there is no QSPI/SPI-flash cache contention with the
+     * DATA-frame interrupt load, so capture DATA frames too. */
+    wifi_promiscuous_filter_t filt = {
+        .filter_mask = WIFI_PROMIS_FILTER_MASK_MGMT | WIFI_PROMIS_FILTER_MASK_DATA,
+    };
+    esp_err_t err = esp_wifi_set_promiscuous_filter(&filt);
+    if (err == ESP_OK) {
+        ESP_LOGI(TAG, "CSI filter upgraded to MGMT+DATA (no display, RuView#893)");
+    } else {
+        ESP_LOGW(TAG, "Failed to enable DATA-frame CSI capture: %s", esp_err_to_name(err));
+    }
+}
+
 void csi_collector_start_hop_timer(void)
 {
     if (s_hop_count <= 1) {
diff --git a/firmware/esp32-csi-node/main/csi_collector.h b/firmware/esp32-csi-node/main/csi_collector.h
index dfb3f20e..92f43105 100644
--- a/firmware/esp32-csi-node/main/csi_collector.h
+++ b/firmware/esp32-csi-node/main/csi_collector.h
@@ -90,6 +90,19 @@ void csi_hop_next_channel(void);
  */
 void csi_collector_start_hop_timer(void);
 
+/**
+ * Upgrade the promiscuous filter to capture DATA frames in addition to MGMT
+ * (RuView#893/#521).
+ *
+ * Called on display-less boards: the MGMT-only filter (the #396 display-crash
+ * workaround set in csi_collector_init) only fires the CSI callback on sparse
+ * management frames, so yield collapses to 0 pps under real traffic and the
+ * node looks dead. A board with no AMOLED panel has no QSPI/SPI-flash cache
+ * contention, so it can safely capture DATA frames — restoring abundant CSI.
+ * Display boards keep MGMT-only to avoid the #396 crash.
+ */
+void csi_collector_enable_data_capture(void);
+
 /**
  * Inject an NDP (Null Data Packet) frame for sensing.
  *
diff --git a/firmware/esp32-csi-node/main/display_task.c b/firmware/esp32-csi-node/main/display_task.c
index 9d834edc..02102497 100644
--- a/firmware/esp32-csi-node/main/display_task.c
+++ b/firmware/esp32-csi-node/main/display_task.c
@@ -9,6 +9,14 @@
 #include "display_task.h"
 #include "sdkconfig.h"
 
+/* Set true once an AMOLED panel is detected and the display task starts.
+ * Defined outside the CONFIG_DISPLAY_ENABLE guard so display_is_active()
+ * exists on headless builds too (where it stays false → CSI captures DATA
+ * frames; see RuView#893). */
+static bool s_display_active = false;
+
+bool display_is_active(void) { return s_display_active; }
+
 #if CONFIG_DISPLAY_ENABLE
 
 #include <string.h>
@@ -162,6 +170,7 @@ esp_err_t display_task_start(void)
 
     ESP_LOGI(TAG, "Display task started (Core %d, priority %d, %d fps)",
              DISP_TASK_CORE, DISP_TASK_PRIORITY, DISP_FPS_LIMIT);
+    s_display_active = true;
     return ESP_OK;
 }
 
diff --git a/firmware/esp32-csi-node/main/display_task.h b/firmware/esp32-csi-node/main/display_task.h
index b5af7060..2b20f8d7 100644
--- a/firmware/esp32-csi-node/main/display_task.h
+++ b/firmware/esp32-csi-node/main/display_task.h
@@ -7,6 +7,7 @@
 #define DISPLAY_TASK_H
 
 #include "esp_err.h"
+#include <stdbool.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -22,6 +23,15 @@ extern "C" {
  */
 esp_err_t display_task_start(void);
 
+/**
+ * @return true once an AMOLED panel has been detected and the display task
+ * is running; false on headless boards (no panel, or built without display
+ * support). Used to choose the CSI promiscuous filter (RuView#893): a board
+ * with no display has no QSPI/SPI-flash contention, so it can safely capture
+ * DATA frames for proper CSI yield instead of starving on MGMT-only.
+ */
+bool display_is_active(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/firmware/esp32-csi-node/main/main.c b/firmware/esp32-csi-node/main/main.c
index ef576890..536bb95f 100644
--- a/firmware/esp32-csi-node/main/main.c
+++ b/firmware/esp32-csi-node/main/main.c
@@ -410,6 +410,21 @@ void app_main(void)
     }
 #endif
 
+    /* RuView#893/#521: the MGMT-only promiscuous filter (set in
+     * csi_collector_init as the #396 display-crash workaround) starves the CSI
+     * callback on display-less boards — yield collapses to 0 pps and the node
+     * looks dead despite being on the network. Now that the display probe has
+     * run, boards with no AMOLED panel (no QSPI/SPI-flash cache contention)
+     * upgrade the filter to capture DATA frames too, restoring CSI yield. */
+#ifdef CONFIG_DISPLAY_ENABLE
+    bool has_display = display_is_active();   /* runtime panel probe result */
+#else
+    bool has_display = false;                 /* display support not compiled in */
+#endif
+    if (!has_display) {
+        csi_collector_enable_data_capture();
+    }
+
     ESP_LOGI(TAG, "CSI streaming active → %s:%d (edge_tier=%u, OTA=%s, WASM=%s, mmWave=%s, swarm=%s, adapt=%s)",
              g_nvs_config.target_ip, g_nvs_config.target_port,
              g_nvs_config.edge_tier,