diff --git a/zephcore/patches/zephyr-new/drivers/lora/lr11xx/lr11xx_lora.c b/zephcore/patches/zephyr-new/drivers/lora/lr11xx/lr11xx_lora.c
index 429f7a9..42cbaaa 100644
--- a/zephcore/patches/zephyr-new/drivers/lora/lr11xx/lr11xx_lora.c
+++ b/zephcore/patches/zephyr-new/drivers/lora/lr11xx/lr11xx_lora.c
@@ -1427,44 +1427,6 @@ uint32_t lr11xx_get_random(const struct device *dev)
 	return random;
 }
 
-void lr11xx_reset_agc(const struct device *dev)
-{
-	struct lr11xx_data *data = dev->data;
-
-	k_mutex_lock(&data->spi_mutex, K_FOREVER);
-
-	/* Warm sleep — powers down analog frontend (resets AGC gain state) */
-	lr11xx_system_sleep_cfg_t sleep_cfg = {
-		.is_warm_start = true,
-		.is_rtc_timeout = false,
-	};
-	lr11xx_system_set_sleep(&data->hal_ctx, sleep_cfg, 0);
-	k_sleep(K_USEC(500));
-
-	/* Wake to STDBY_RC for calibration */
-	lr11xx_system_set_standby(&data->hal_ctx, LR11XX_SYSTEM_STANDBY_CFG_RC);
-
-	/* Recalibrate all blocks */
-	lr11xx_system_calibrate(&data->hal_ctx, 0x3F);
-
-	/* Re-calibrate image rejection for the actual operating frequency */
-	if (data->configured) {
-		uint16_t freq_mhz = data->modem_cfg.frequency / 1000000;
-		lr11xx_system_calibrate_image_in_mhz(&data->hal_ctx,
-						     freq_mhz - 4, freq_mhz + 4);
-	}
-
-	/* Re-apply RX boost if it was enabled */
-	if (data->rx_boost_enabled) {
-		lr11xx_radio_cfg_rx_boosted(&data->hal_ctx, true);
-		lr11xx_system_clear_irq_status(&data->hal_ctx,
-					       LR11XX_SYSTEM_IRQ_ALL_MASK);
-		data->rx_boost_applied = true;
-	}
-
-	k_mutex_unlock(&data->spi_mutex);
-}
-
 /* ── Deferred hardware init (runs on first lora_config call) ────────── */
 
 /* ── Driver API: CAD ────────────────────────────────────────────────── */
diff --git a/zephcore/patches/zephyr-new/drivers/lora/lr11xx/lr11xx_lora.h b/zephcore/patches/zephyr-new/drivers/lora/lr11xx/lr11xx_lora.h
index a22879e..701de81 100644
--- a/zephcore/patches/zephyr-new/drivers/lora/lr11xx/lr11xx_lora.h
+++ b/zephcore/patches/zephyr-new/drivers/lora/lr11xx/lr11xx_lora.h
@@ -95,19 +95,6 @@ void lr11xx_reset_dc_timeout_restarts(const struct device *dev);
  */
 uint32_t lr11xx_get_random(const struct device *dev);
 
-/**
- * @brief Reset AGC by performing warm sleep + full recalibration
- *
- * Warm sleep powers down the analog frontend (resets AGC gain state),
- * then Calibrate(0x3F) refreshes all blocks. Re-applies image
- * calibration for the operating frequency and RX boost afterward.
- *
- * Must be called while NOT actively receiving a packet.
- *
- * @param dev LoRa device
- */
-void lr11xx_reset_agc(const struct device *dev);
-
 /**
  * @brief Set the adaptive-CAD operating detPeak offset
  *
diff --git a/zephcore/patches/zephyr-new/drivers/lora/lr20xx/lr20xx_lora.c b/zephcore/patches/zephyr-new/drivers/lora/lr20xx/lr20xx_lora.c
index ffee9e4..f2476e7 100644
--- a/zephcore/patches/zephyr-new/drivers/lora/lr20xx/lr20xx_lora.c
+++ b/zephcore/patches/zephyr-new/drivers/lora/lr20xx/lr20xx_lora.c
@@ -491,10 +491,10 @@ static lr20xx_status_t lr20xx_calibrate_front_end(void *ctx, uint32_t freq_hz);
  * because the patch supersedes them.
  *
  * The image is volatile: lost on reset and on cold start, preserved by sleep
- * with retention (§22.3).  Every sleep this driver issues sets retention
- * (lr20xx_reset_agc), and duty-cycle sleep is retention by definition (§6.3.8),
- * so the reset paths are the only places it has to be (re)loaded.  Costs 2240
- * bytes of flash and +80 nA of retention sleep current.
+ * with retention (§22.3).  Duty-cycle sleep is retention by definition (§6.3.8)
+ * and this driver issues no other sleep, so the reset paths are the only places
+ * it has to be (re)loaded.  Costs 2240 bytes of flash and +80 nA of retention
+ * sleep current.
  *
  * Best-effort: a chip without the patch still works, so a failure here is a
  * warning, not a reason to fail init. */
@@ -609,7 +609,7 @@ static void lr20xx_hardware_reset(struct lr20xx_data *data,
 	 * caller of this function is post-config (the DIO1 stuck-recovery path
 	 * and three standby-failure paths), and lr20xx_start_rx() follows
 	 * immediately, so calibrate for the frequency actually about to be
-	 * received on.  Same shape as lr20xx_reset_agc(). */
+	 * received on. */
 	if (data->configured) {
 		lr20xx_calibrate_front_end(ctx, data->modem_cfg.frequency);
 	}
@@ -975,6 +975,32 @@ static bool lr20xx_apply_rx_duty_cycle(struct lr20xx_data *data)
 		return false;
 	}
 
+	/* Re-apply RX boost before re-arming — same warm-start caution as
+	 * lr11xx_restart_rx(), which has always done this on its duty-cycle
+	 * path.  A duty cycle sleeps the chip between every window (DS §6.3.8),
+	 * and DS §6.3.4 (SetAdditionalRegToRetain, "specifies the address of an
+	 * additional register to retain in Sleep mode") establishes that not
+	 * every register survives that on its own.  This driver holds no
+	 * retention entries at all, and the only place set_rx_path was ever
+	 * issued is apply_modem_config() — which the re-arm path never calls, so
+	 * before this the boost was programmed once at RX entry and never again.
+	 * If it does not survive the sleep, every window after the first ran
+	 * 3 dB down: the same failure the SX126x hit, where the fix was pinning
+	 * RX gain into the warm-start retention list.
+	 *
+	 * One SPI command, correct either way.  Whether the LR2021 actually needs
+	 * it — or wants a retention entry instead — is still an open question;
+	 * read the gain back after a window, or A/B it on PDR.
+	 *
+	 * Not conditioned on rx_boost_applied: that flag tracks what we
+	 * programmed, not what survived. */
+	if (data->rx_boost_enabled) {
+		lr20xx_radio_common_set_rx_path(
+			ctx, LR20XX_RADIO_COMMON_RX_PATH_LF,
+			LR20XX_RADIO_COMMON_RX_PATH_BOOST_MODE_7);
+		data->rx_boost_applied = true;
+	}
+
 	/* Clear the CMD_PERR the HAL's clockless wake frame provokes: it is
 	 * self-inflicted by the wake and says nothing about the command below.
 	 * Left set it holds DIO1 high and poisons the re-arm. */
@@ -2120,6 +2146,28 @@ static int lr20xx_lora_recv_async(const struct device *dev,
 
 	k_mutex_lock(&data->spi_mutex, K_FOREVER);
 
+	/* Idempotent fast path: the chip is already in continuous RX, so there
+	 * is nothing to program — refresh the callback and leave the receiver on
+	 * air.  The usual caller is LoRaRadioBase::startSendRaw()'s failure path:
+	 * the LBT branch of send_async has already run lr20xx_start_rx() before
+	 * returning -EBUSY, so without this every CAD-busy verdict paid a SECOND
+	 * full rebuild (standby -> ClearRxFifo -> apply_modem_config -> SetRx) on
+	 * top of the driver's own.  startSendRaw's comment has asserted this was
+	 * "a no-op there" ever since the SX126x gained its Phase 2 fast path; on
+	 * this driver it was not, until now.
+	 *
+	 * rx_duty_cycle_enabled is part of the guard, not decoration.  This is
+	 * the CONTINUOUS entry point and it clears that flag below, so a caller
+	 * moving a duty-cycled radio to continuous RX has to take the full path:
+	 * fast-pathing there would leave the cycle running on a chip whose
+	 * bookkeeping claims continuous, and nothing would ever stand it down. */
+	if (data->in_rx_mode && !data->rx_duty_cycle_enabled) {
+		data->async_rx_cb = cb;
+		data->async_rx_user_data = user_data;
+		k_mutex_unlock(&data->spi_mutex);
+		return 0;
+	}
+
 	data->async_rx_cb = cb;
 	data->async_rx_user_data = user_data;
 	data->rx_duty_cycle_enabled = false;
@@ -2511,42 +2559,6 @@ uint32_t lr20xx_get_random(const struct device *dev)
 	return random;
 }
 
-void lr20xx_reset_agc(const struct device *dev)
-{
-	struct lr20xx_data *data = dev->data;
-	void *ctx = &data->hal_ctx;
-
-	k_mutex_lock(&data->spi_mutex, K_FOREVER);
-
-	/* Warm sleep — powers down analog frontend (resets AGC gain state).
-	 * is_ram_retention_enabled=true = warm sleep (equivalent to LR11xx warm_start). */
-	lr20xx_system_sleep_cfg_t sleep_cfg = {
-		.is_clk_32k_enabled       = false,
-		.is_ram_retention_enabled = true,
-	};
-	/* No delay after the sleep opcode — lr20xx_hal_write() already does a
-	 * k_busy_wait(1000) when it sees 0x0127, so this was a duplicate guard
-	 * (and k_sleep() with a sub-tick duration rounds up to a full tick). */
-	lr20xx_system_set_sleep_mode(ctx, &sleep_cfg, 0);
-
-	lr20xx_system_set_standby_mode(ctx, LR20XX_SYSTEM_STANDBY_MODE_RC);
-
-	lr20xx_system_calibrate(ctx, 0x6F);
-
-	if (data->configured) {
-		lr20xx_calibrate_front_end(ctx, data->modem_cfg.frequency);
-	}
-
-	if (data->rx_boost_enabled) {
-		lr20xx_radio_common_set_rx_path(
-			ctx, LR20XX_RADIO_COMMON_RX_PATH_LF,
-			LR20XX_RADIO_COMMON_RX_PATH_BOOST_MODE_7);
-		data->rx_boost_applied = true;
-	}
-
-	k_mutex_unlock(&data->spi_mutex);
-}
-
 /* ── Driver API: CAD ────────────────────────────────────────────────── */
 
 /* Datasheet Table 6-19 in full: rows = CAD symbol count 1..4, columns =
@@ -2852,8 +2864,31 @@ static int lr20xx_lora_recv_duty_cycle(const struct device *dev,
 		return -EINVAL;
 	}
 
+	uint32_t rx_ms = k_ticks_to_ms_ceil32(rx_period.ticks);
+	uint32_t slp_ms = k_ticks_to_ms_ceil32(sleep_period.ticks);
+	if (rx_ms < 1) rx_ms = 1;
+	if (slp_ms < 1) slp_ms = 1;
+
 	k_mutex_lock(&data->spi_mutex, K_FOREVER);
 
+	/* Idempotent fast path, the duty-cycle counterpart of the one in
+	 * recv_async and the same shape as the SX126x's: a cycle already armed
+	 * on exactly these periods has nothing to re-arm, so refresh the
+	 * callback and stay on air instead of tearing a live cycle down and
+	 * paying a full rebuild for it.  Timings are computed before the lock so
+	 * they can be compared here.
+	 *
+	 * Any other combination — continuous RX, or a cycle on different periods
+	 * — falls through to the full path below, which re-arms via
+	 * lr20xx_apply_rx_duty_cycle() and therefore still gets the AGC reset. */
+	if (data->in_rx_mode && data->rx_duty_cycle_enabled &&
+	    data->dc_rx_ms == rx_ms && data->dc_sleep_ms == slp_ms) {
+		data->async_rx_cb = cb;
+		data->async_rx_user_data = user_data;
+		k_mutex_unlock(&data->spi_mutex);
+		return 0;
+	}
+
 	data->async_rx_cb = cb;
 	data->async_rx_user_data = user_data;
 
@@ -2864,11 +2899,6 @@ static int lr20xx_lora_recv_duty_cycle(const struct device *dev,
 	lr20xx_radio_fifo_clear_rx(ctx);
 	lr20xx_apply_modem_config(data, cfg, false);
 
-	uint32_t rx_ms = k_ticks_to_ms_ceil32(rx_period.ticks);
-	uint32_t slp_ms = k_ticks_to_ms_ceil32(sleep_period.ticks);
-	if (rx_ms < 1) rx_ms = 1;
-	if (slp_ms < 1) slp_ms = 1;
-
 	/* Store for the re-arm paths (lr20xx_start_rx / lr20xx_restart_rx)
 	 * so every re-entry uses exactly this timing. */
 	data->dc_rx_ms = rx_ms;
diff --git a/zephcore/patches/zephyr-new/drivers/lora/lr20xx/lr20xx_lora.h b/zephcore/patches/zephyr-new/drivers/lora/lr20xx/lr20xx_lora.h
index 6bb6512..20a54fc 100644
--- a/zephcore/patches/zephyr-new/drivers/lora/lr20xx/lr20xx_lora.h
+++ b/zephcore/patches/zephyr-new/drivers/lora/lr20xx/lr20xx_lora.h
@@ -168,13 +168,6 @@ int lr20xx_configure_side_detectors(const struct device *dev,
  */
 uint32_t lr20xx_get_random(const struct device *dev);
 
-/**
- * @brief Reset AGC by performing warm sleep + full recalibration
- *
- * @param dev LoRa device
- */
-void lr20xx_reset_agc(const struct device *dev);
-
 /**
  * @brief Set the adaptive-CAD operating detPeak offset
  *
diff --git a/zephcore/src/Dispatcher.cpp b/zephcore/src/Dispatcher.cpp
index 559cff3..bf41cb5 100644
--- a/zephcore/src/Dispatcher.cpp
+++ b/zephcore/src/Dispatcher.cpp
@@ -517,6 +517,32 @@ void Dispatcher::checkSend()
 				 * continuously on a busy site and buries real
 				 * faults. */
 				LOG_DBG("checkSend: startSendRaw refused, re-queuing delay=%u", retry);
+
+				/* Escalate a refusal that will not end.  This branch
+				 * used to leave cad_busy_start alone, so a packet the
+				 * driver's own LBT kept rejecting — the pre-TX gate
+				 * having passed — looped indefinitely with no counter,
+				 * no error flag and nothing above DBG.  At default log
+				 * level a node in that state looks completely idle
+				 * while it never transmits, which is exactly how a
+				 * chip-side CAD (LR20xx CAD_LBT) fails.
+				 *
+				 * Deliberately no recoverRxState() here, unlike the
+				 * isReceiving() branch above: that one recovers a chip
+				 * suspected of being stuck in RX, whereas a busy
+				 * channel is a true reading and walking the radio
+				 * through REST would only add deaf time. Report and
+				 * keep retrying. */
+				if (cad_busy_start == 0) {
+					cad_busy_start = now;
+				} else if (now - cad_busy_start > getCADFailMaxDuration()) {
+					_err_flags |= ERR_EVENT_CAD_TIMEOUT;
+					LOG_WRN("checkSend: LBT has refused TX for %ums "
+						"(len=%d, noise=%d) — channel busy or CAD too sensitive",
+						(unsigned)(now - cad_busy_start), len,
+						_radio->getNoiseFloor());
+					cad_busy_start = now;
+				}
 				logTxFail(outbound, outbound->getRawLength());
 				_mgr->queueOutbound(outbound, outbound_priority, futureMillis((int)retry));
 				outbound = nullptr;
@@ -525,6 +551,12 @@ void Dispatcher::checkSend()
 				}
 			} else {
 				outbound_expiry = futureMillis((int)max_airtime);
+				/* A transmit got out, so the refusal streak above is
+				 * over.  Without this the timer keeps running across
+				 * successful sends and the next isolated refusal
+				 * inherits a stale start, reporting a stall that
+				 * already ended. */
+				cad_busy_start = 0;
 			}
 		}
 	}
diff --git a/zephcore/src/main_companion.cpp b/zephcore/src/main_companion.cpp
index 0d5f48a..b1a45d5 100644
--- a/zephcore/src/main_companion.cpp
+++ b/zephcore/src/main_companion.cpp
@@ -511,9 +511,9 @@ static void mesh_event_loop(void)
 
 		/* Periodic housekeeping — maintenance + UI refresh */
 		if (events & MESH_EVENT_HOUSEKEEPING) {
-			/* Radio maintenance: noise floor calibration, AGC reset,
-			 * RX watchdog.  Separated from loop() so these never run
-			 * on packet-driven events. */
+			/* Radio maintenance: noise floor calibration, adaptive-CAD
+			 * probe, RX watchdog.  Separated from loop() so these
+			 * never run on packet-driven events. */
 			if (companion_mesh_ptr) {
 				companion_mesh_ptr->maintenanceLoop();
 			}
diff --git a/zephcore/src/main_room_server.cpp b/zephcore/src/main_room_server.cpp
index 66607fc..b1be665 100644
--- a/zephcore/src/main_room_server.cpp
+++ b/zephcore/src/main_room_server.cpp
@@ -443,9 +443,9 @@ static void room_event_loop(void)
 		/* Periodic housekeeping — maintenance + display refresh */
 		if (events & MESH_EVENT_HOUSEKEEPING) {
 #ifdef ZEPHCORE_LORA
-			/* Radio maintenance: noise floor calibration, AGC reset,
-			 * RX watchdog.  Separated from loop() so these never run
-			 * on packet-driven events. */
+			/* Radio maintenance: noise floor calibration, adaptive-CAD
+			 * probe, RX watchdog.  Separated from loop() so these
+			 * never run on packet-driven events. */
 			if (room_mesh_ptr) {
 				room_mesh_ptr->maintenanceLoop();
 				/* Also drive loop() so time-based actions (advert