diff --git a/src/helpers/nrf52/SerialBLEInterface.cpp b/src/helpers/nrf52/SerialBLEInterface.cpp
index 75a4e3b0..345daa9a 100644
--- a/src/helpers/nrf52/SerialBLEInterface.cpp
+++ b/src/helpers/nrf52/SerialBLEInterface.cpp
@@ -7,6 +7,9 @@
 // Magic numbers came from actual testing
 #define BLE_HEALTH_CHECK_INTERVAL  10000  // Advertising watchdog check every 10 seconds
 #define BLE_RETRY_THROTTLE_MS      250    // Throttle retries to 250ms when queue buildup detected
+#define BLE_RETRY_THROTTLE_MAX_MS  2000   // Cap for backoff below — a marginal link that keeps
+                                           // failing the (blocking, up to 100ms) send shouldn't get
+                                           // re-probed every 250ms, stealing ~40% of loop time
 
 // Connection parameters (units: interval=1.25ms, timeout=10ms)
 #define BLE_MIN_CONN_INTERVAL      12     // 15ms
@@ -205,6 +208,7 @@ void SerialBLEInterface::clearBuffers() {
   send_queue_len = 0;
   recv_queue_len = 0;
   _last_retry_attempt = 0;
+  _retry_backoff_ms = 0;
   bleuart.flush();
 }
 
@@ -302,7 +306,8 @@ size_t SerialBLEInterface::checkRecvFrame(uint8_t dest[]) {
       send_queue_len = 0;
     } else {
       unsigned long now = millis();
-      bool throttle_active = (_last_retry_attempt > 0 && (now - _last_retry_attempt) < BLE_RETRY_THROTTLE_MS);
+      unsigned long throttle_ms = _retry_backoff_ms > 0 ? _retry_backoff_ms : BLE_RETRY_THROTTLE_MS;
+      bool throttle_active = (_last_retry_attempt > 0 && (now - _last_retry_attempt) < throttle_ms);
 
       if (!throttle_active) {
         Frame frame_to_send = send_queue[0];
@@ -311,19 +316,28 @@ size_t SerialBLEInterface::checkRecvFrame(uint8_t dest[]) {
         if (written == frame_to_send.len) {
           BLE_DEBUG_PRINTLN("writeBytes: sz=%u, hdr=%u", (unsigned)frame_to_send.len, (unsigned)frame_to_send.buf[0]);
           _last_retry_attempt = 0;
+          _retry_backoff_ms = 0;
           shiftSendQueueLeft();
         } else if (written > 0) {
           BLE_DEBUG_PRINTLN("writeBytes: partial write, sent=%u of %u, dropping corrupted frame", (unsigned)written, (unsigned)frame_to_send.len);
           _last_retry_attempt = 0;
+          _retry_backoff_ms = 0;
           shiftSendQueueLeft();
         } else {
           if (!isConnected()) {
             BLE_DEBUG_PRINTLN("writeBytes failed: connection lost, dropping frame");
             _last_retry_attempt = 0;
+            _retry_backoff_ms = 0;
             shiftSendQueueLeft();
           } else {
-            BLE_DEBUG_PRINTLN("writeBytes failed (buffer full), keeping frame for retry");
+            // Send blocked (peer not ACKing — e.g. marginal link range). Each attempt above can
+            // itself block up to 100ms (Bluefruit's notify() waits on a free HVN packet slot), so
+            // back off exponentially instead of re-probing every fixed 250ms — otherwise a
+            // sustained bad link steals ~40% of loop time indefinitely.
+            BLE_DEBUG_PRINTLN("writeBytes failed (buffer full), keeping frame for retry, backoff=%lums", throttle_ms);
             _last_retry_attempt = now;
+            unsigned long next = throttle_ms * 2;
+            _retry_backoff_ms = next > BLE_RETRY_THROTTLE_MAX_MS ? BLE_RETRY_THROTTLE_MAX_MS : next;
           }
         }
       }
diff --git a/src/helpers/nrf52/SerialBLEInterface.h b/src/helpers/nrf52/SerialBLEInterface.h
index de103054..b48b6660 100644
--- a/src/helpers/nrf52/SerialBLEInterface.h
+++ b/src/helpers/nrf52/SerialBLEInterface.h
@@ -15,6 +15,7 @@ class SerialBLEInterface : public BaseSerialInterface {
   uint16_t _conn_handle;
   unsigned long _last_health_check;
   unsigned long _last_retry_attempt;
+  unsigned long _retry_backoff_ms;   // 0 == not yet backed off; grows on repeated failed sends
 
   struct Frame {
     uint8_t len;
@@ -49,6 +50,7 @@ public:
     _conn_handle = BLE_CONN_HANDLE_INVALID;
     _last_health_check = 0;
     _last_retry_attempt = 0;
+    _retry_backoff_ms = 0;
     send_queue_len = 0;
     recv_queue_len = 0;
   }