diff --git a/nimble/drivers/nrf5x/src/ble_phy.c b/nimble/drivers/nrf5x/src/ble_phy.c
index 3deec7dd63..7f73f04ecd 100644
--- a/nimble/drivers/nrf5x/src/ble_phy.c
+++ b/nimble/drivers/nrf5x/src/ble_phy.c
@@ -583,6 +583,31 @@ ble_phy_rxpdu_copy(uint8_t *dptr, struct os_mbuf *rxpdu)
            sizeof(struct ble_mbuf_hdr));
 }
 
+/**
+ * There is no way on nRF5 to disable a COMPARE event entirely.  So we fake
+ * it, by setting it as far in the future as possible (by triggering a
+ * capture to it), and then clearing the event if it was set.
+ */
+static void
+timer0_safely_reset(int cc)
+{
+    nrf_timer_task_trigger(NRF_TIMER0, nrf_timer_capture_task_get(cc));
+    NRF_TIMER0->EVENTS_COMPARE[cc] = 0;
+}
+
+/**
+ * It is possible that we set up a timer, but we were too late -- it didn't
+ * fire.  Detect when this happens, reliably, by capturing the current time
+ * to a scratch counter and comparing with wraparound.
+ */
+static bool
+timer0_did_miss(int cc, int cc_scratch)
+{
+    nrf_timer_task_trigger(NRF_TIMER0, nrf_timer_capture_task_get(cc_scratch));
+    uint32_t ticks_rem = NRF_TIMER0->CC[cc] - NRF_TIMER0->CC[cc_scratch];
+    return (ticks_rem >= 0x80000000) && !NRF_TIMER0->EVENTS_COMPARE[cc];
+}
+
 /**
  * Called when we want to wait if the radio is in either the rx or tx
  * disable states. We want to wait until that state is over before doing
@@ -885,13 +910,13 @@ ble_phy_wfr_enable(int txrx, uint8_t tx_phy_mode, uint32_t wfr_usecs)
     /* Adjust for delay between actual access address RX and EVENT_ADDRESS */
     end_time += g_ble_phy_t_rxaddrdelay[phy];
 
-    /* wfr_secs is the time from rxen until timeout */
-    nrf_timer_cc_set(NRF_TIMER0, 3, end_time);
-    NRF_TIMER0->EVENTS_COMPARE[3] = 0;
-
     /* Enable wait for response PPI */
+    timer0_safely_reset(3);
     phy_ppi_wfr_enable();
 
+    /* wfr_secs is the time from rxen until timeout */
+    nrf_timer_cc_set(NRF_TIMER0, 3, end_time);
+
     /*
      * It may happen that if CPU is halted for a brief moment (e.g. during flash
      * erase or write), TIMER0 already counted past CC[3] and thus wfr will not
@@ -904,8 +929,7 @@ ble_phy_wfr_enable(int txrx, uint8_t tx_phy_mode, uint32_t wfr_usecs)
      * CC[1] is only used as a reference on RX start, we do not need it here so
      * it can be used to read TIMER0 counter.
      */
-    nrf_timer_task_trigger(NRF_TIMER0, NRF_TIMER_TASK_CAPTURE1);
-    if (NRF_TIMER0->CC[1] > NRF_TIMER0->CC[3]) {
+    if (timer0_did_miss(3, 1 /* scratch */)) {
         phy_ppi_wfr_disable();
         nrf_radio_task_trigger(NRF_RADIO, NRF_RADIO_TASK_DISABLE);
     }
@@ -1096,15 +1120,15 @@ ble_phy_tx_end_isr(void)
 
 #if PHY_USE_FEM_LNA
         fem_time = rx_time - MYNEWT_VAL(BLE_FEM_LNA_TURN_ON_US);
-        nrf_timer_cc_set(NRF_TIMER0, 2, fem_time);
-        NRF_TIMER0->EVENTS_COMPARE[2] = 0;
+        timer0_safely_reset(2);
         phy_fem_enable_lna();
+        nrf_timer_cc_set(NRF_TIMER0, 2, fem_time);
 #endif
 
         radio_time = rx_time - BLE_PHY_T_RXENFAST;
-        nrf_timer_cc_set(NRF_TIMER0, 0, radio_time);
-        NRF_TIMER0->EVENTS_COMPARE[0] = 0;
+        timer0_safely_reset(0);
         phy_ppi_timer0_compare0_to_radio_rxen_enable();
+        nrf_timer_cc_set(NRF_TIMER0, 0, radio_time);
 
         /* In case TIMER0 did already count past CC[0] and/or CC[2], radio
          * and/or LNA may not be enabled. In any case we won't be stuck since
@@ -1142,18 +1166,17 @@ ble_phy_tx_end_isr(void)
         tx_time -= g_ble_phy_t_txdelay[g_ble_phy_data.phy_cur_phy_mode];
 
         radio_time = tx_time - BLE_PHY_T_TXENFAST;
-        nrf_timer_cc_set(NRF_TIMER0, 0, radio_time);
-        NRF_TIMER0->EVENTS_COMPARE[0] = 0;
+        timer0_safely_reset(0);
         phy_ppi_timer0_compare0_to_radio_txen_enable();
+        nrf_timer_cc_set(NRF_TIMER0, 0, radio_time);
 
 #if PHY_USE_FEM_PA
-        nrf_timer_cc_set(NRF_TIMER0, 2, fem_time);
-        NRF_TIMER0->EVENTS_COMPARE[2] = 0;
+        timer0_safely_reset(2);
         phy_fem_enable_pa();
+        nrf_timer_cc_set(NRF_TIMER0, 2, fem_time);
 #endif
 
-        nrf_timer_task_trigger(NRF_TIMER0, NRF_TIMER_TASK_CAPTURE3);
-        if (NRF_TIMER0->CC[3] > NRF_TIMER0->CC[0]) {
+        if (timer0_did_miss(0, 3 /* scratch */)) {
             phy_ppi_timer0_compare0_to_radio_txen_disable();
             g_ble_phy_data.phy_transition_late = 1;
         }
@@ -1292,14 +1315,14 @@ ble_phy_rx_end_isr(void)
     tx_time -= g_ble_phy_t_txdelay[g_ble_phy_data.phy_cur_phy_mode];
 
     radio_time = tx_time - BLE_PHY_T_TXENFAST;
-    nrf_timer_cc_set(NRF_TIMER0, 0, radio_time);
-    NRF_TIMER0->EVENTS_COMPARE[0] = 0;
+    timer0_safely_reset(0);
     phy_ppi_timer0_compare0_to_radio_txen_enable();
+    nrf_timer_cc_set(NRF_TIMER0, 0, radio_time);
 
 #if PHY_USE_FEM_PA
-    nrf_timer_cc_set(NRF_TIMER0, 2, fem_time);
-    NRF_TIMER0->EVENTS_COMPARE[2] = 0;
+    timer0_safely_reset(2);
     phy_fem_enable_pa();
+    nrf_timer_cc_set(NRF_TIMER0, 2, fem_time);
 #endif
 
     /* Need to check if TIMER0 did not already count past CC[0] and/or CC[2], so
@@ -1308,11 +1331,9 @@ ble_phy_rx_end_isr(void)
      *
      * Note: CC[3] is used only for wfr which we do not need here.
      */
-    nrf_timer_task_trigger(NRF_TIMER0, NRF_TIMER_TASK_CAPTURE3);
-    is_late = (NRF_TIMER0->CC[3] > radio_time) && !NRF_TIMER0->EVENTS_COMPARE[0];
+    is_late = timer0_did_miss(0, 3 /* scratch */);
 #if PHY_USE_FEM_PA
-    is_late = is_late ||
-              ((NRF_TIMER0->CC[3] > fem_time) && !NRF_TIMER0->EVENTS_COMPARE[2]);
+    is_late = is_late || timer0_did_miss(2, 3 /* scratch */);
 #endif
     if (is_late) {
         phy_ppi_timer0_compare0_to_radio_txen_disable();