diff --git a/examples/platforms/efr32mg12/Makefile.am b/examples/platforms/efr32mg12/Makefile.am
index 8c3668051..72354f670 100644
--- a/examples/platforms/efr32mg12/Makefile.am
+++ b/examples/platforms/efr32mg12/Makefile.am
@@ -46,6 +46,7 @@ libopenthread_efr32mg12_a_CPPFLAGS                                            =
     -D__START=main                                                              \
     -D__STARTUP_CLEAR_BSS                                                       \
     -DPLATFORM_HEADER=\"@top_builddir@/third_party/silabs/gecko_sdk_suite/v2.6/platform/base/hal/micro/cortexm3/compiler/gcc.h\" \
+    -DNVIC_CONFIG=\"platform/base/hal/micro/cortexm3/efm32/nvic-config.h\"      \
     -Wno-sign-compare                                                           \
     -DCORTEXM3                                                                  \
     -DPHY=EMBER_PHY_RAIL                                                        \
diff --git a/examples/platforms/efr32mg12/alarm.c b/examples/platforms/efr32mg12/alarm.c
index 9ae66e57a..d031fbeee 100644
--- a/examples/platforms/efr32mg12/alarm.c
+++ b/examples/platforms/efr32mg12/alarm.c
@@ -36,6 +36,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#include "openthread-system.h"
 #include <openthread/config.h>
 #include <openthread/platform/alarm-milli.h>
 #include <openthread/platform/diag.h>
@@ -67,6 +68,7 @@ static bool     sIsRunning = false;
 
 static void RAILCb_TimerExpired(RAIL_Handle_t aHandle)
 {
+    otSysEventSignalPending();
 }
 
 void efr32AlarmInit(void)
diff --git a/examples/platforms/efr32mg12/radio.c b/examples/platforms/efr32mg12/radio.c
index 204f41d0a..f31992344 100644
--- a/examples/platforms/efr32mg12/radio.c
+++ b/examples/platforms/efr32mg12/radio.c
@@ -34,6 +34,7 @@
 
 #include <assert.h>
 
+#include "openthread-system.h"
 #include <openthread/config.h>
 #include <openthread/platform/alarm-milli.h>
 #include <openthread/platform/diag.h>
@@ -55,7 +56,6 @@
 #include "rail.h"
 #include "rail_config.h"
 #include "rail_ieee802154.h"
-#include "rtcdriver.h"
 
 enum
 {
@@ -289,7 +289,7 @@ void efr32RadioInit(void)
     efr32ConfigInit(RAILCb_Generic);
 
     CMU_ClockEnable(cmuClock_PRS, true);
-    RTCDRV_Init();
+
     status = RAIL_ConfigSleep(gRailHandle, RAIL_SLEEP_CONFIG_TIMERSYNC_ENABLED);
     assert(status == RAIL_STATUS_NO_ERROR);
 
@@ -704,6 +704,8 @@ static void processNextRxPacket(otInstance *aInstance)
         }
     }
 
+    otSysEventSignalPending();
+
 exit:
 
     if (packetHandle != RAIL_RX_PACKET_HANDLE_INVALID)
@@ -801,6 +803,8 @@ static void RAILCb_Generic(RAIL_Handle_t aRailHandle, RAIL_Events_t aEvents)
             sEnergyScanResultDbm = energyScanResultQuarterDbm / QUARTER_DBM_IN_DBM;
         }
     }
+
+    otSysEventSignalPending();
 }
 
 otError otPlatRadioEnergyScan(otInstance *aInstance, uint8_t aScanChannel, uint16_t aScanDuration)
@@ -835,11 +839,14 @@ void efr32RadioProcess(otInstance *aInstance)
         {
             otPlatRadioTxDone(aInstance, &sTransmitFrame, &sReceiveFrame, sTransmitError);
         }
+
+        otSysEventSignalPending();
     }
     else if (sEnergyScanMode == ENERGY_SCAN_MODE_ASYNC && sEnergyScanStatus == ENERGY_SCAN_STATUS_COMPLETED)
     {
         sEnergyScanStatus = ENERGY_SCAN_STATUS_IDLE;
         otPlatRadioEnergyScanDone(aInstance, sEnergyScanResultDbm);
+        otSysEventSignalPending();
     }
 
     processNextRxPacket(aInstance);
diff --git a/examples/platforms/efr32mg12/system.c b/examples/platforms/efr32mg12/system.c
index dff36008f..d51c464ce 100644
--- a/examples/platforms/efr32mg12/system.c
+++ b/examples/platforms/efr32mg12/system.c
@@ -34,6 +34,7 @@
 
 #include <string.h>
 
+#include "openthread-system.h"
 #include <openthread/tasklet.h>
 #include <openthread/platform/uart.h>
 
@@ -70,17 +71,28 @@ void otSysInit(int argc, char *argv[])
     OT_UNUSED_VARIABLE(argc);
     OT_UNUSED_VARIABLE(argv);
 
+    __disable_irq();
+
+#undef FIXED_EXCEPTION
+#define FIXED_EXCEPTION(vectorNumber, functionName, deviceIrqn, deviceIrqHandler)
+#define EXCEPTION(vectorNumber, functionName, deviceIrqn, deviceIrqHandler, priorityLevel, subpriority) \
+    NVIC_SetPriority(deviceIrqn, NVIC_EncodePriority(PRIGROUP_POSITION, priorityLevel, subpriority));
+#include NVIC_CONFIG
+#undef EXCEPTION
+
+    NVIC_SetPriorityGrouping(PRIGROUP_POSITION);
     CHIP_Init();
-
     halInitChipSpecific();
-
     BSP_Init(BSP_INIT_BCC);
+    RTCDRV_Init();
 
 #if (HAL_FEM_ENABLE)
     initFem();
     wakeupFem();
 #endif
 
+    __enable_irq();
+
 #if USE_EFR32_LOG
     efr32LogInit();
 #endif
@@ -153,3 +165,8 @@ void otSysProcessDrivers(otInstance *aInstance)
     efr32RadioProcess(aInstance);
     efr32AlarmProcess(aInstance);
 }
+
+__WEAK void otSysEventSignalPending(void)
+{
+    // Intentionally empty
+}
diff --git a/examples/platforms/efr32mg12/uart.c b/examples/platforms/efr32mg12/uart.c
index 8402acca4..36858acd8 100644
--- a/examples/platforms/efr32mg12/uart.c
+++ b/examples/platforms/efr32mg12/uart.c
@@ -34,6 +34,7 @@
 
 #include <stddef.h>
 
+#include "openthread-system.h"
 #include <openthread/platform/uart.h>
 
 #include "utils/code_utils.h"
@@ -132,6 +133,8 @@ static void receiveDone(UARTDRV_Handle_t aHandle, Ecode_t aStatus, uint8_t *aDat
         assert(sReceiveDeferred == false);
         sReceiveDeferred = true;
     }
+
+    otSysEventSignalPending();
 }
 
 static inline bool isBufferEmpty(uint16_t unwrappedReadStart, uint16_t unwrappedReadEnd)
@@ -180,6 +183,7 @@ exit:
 static void transmitDone(UARTDRV_Handle_t aHandle, Ecode_t aStatus, uint8_t *aData, UARTDRV_Count_t aCount)
 {
     sTransmitLength = 0;
+    otSysEventSignalPending();
 }
 
 static void processReceive(void)