diff --git a/modules/hal_nordic/nrf_802154/sl_opensource/platform/nrf_802154_clock_zephyr.c b/modules/hal_nordic/nrf_802154/sl_opensource/platform/nrf_802154_clock_zephyr.c
index 87aa85261e9..3d18ad6077a 100644
--- a/modules/hal_nordic/nrf_802154/sl_opensource/platform/nrf_802154_clock_zephyr.c
+++ b/modules/hal_nordic/nrf_802154/sl_opensource/platform/nrf_802154_clock_zephyr.c
@@ -44,6 +44,19 @@ static void hfclk_on_callback(struct onoff_manager *mgr,
 }
 
 #if defined(CONFIG_CLOCK_CONTROL_NRF)
+
+#if defined(NRF54LM20A_ENGA_XXAA)
+/* HF clock time to ramp-up. */
+#define MAX_HFXO_RAMP_UP_TIME_US 550
+
+static void hfclk_started_timer_handler(struct k_timer *dummy)
+{
+	hfclk_on_callback(NULL, NULL, 0, 0);
+}
+
+K_TIMER_DEFINE(hfclk_started_timer, hfclk_started_timer_handler, NULL);
+#endif
+
 void nrf_802154_clock_hfclk_start(void)
 {
 	struct onoff_manager *mgr =
@@ -64,6 +77,15 @@ void nrf_802154_clock_hfclk_start(void)
 	int ret = onoff_request(mgr, &hfclk_cli);
 	__ASSERT_NO_MSG(ret >= 0);
 	(void)ret;
+
+	#if defined(NRF54LM20A_ENGA_XXAA)
+		/*
+		 * Right now, the power_clock_irq is not available on nRF54LM20A.
+		 * Since the onoff mechanism relies on the irq, the timer is used
+		 * to emit the hfclk_ready callback.
+		 */
+		k_timer_start(&hfclk_started_timer, K_USEC(MAX_HFXO_RAMP_UP_TIME_US), K_NO_WAIT);
+	#endif
 }
 
 void nrf_802154_clock_hfclk_stop(void)