diff --git a/examples/platforms/nrf528xx/src/flash.c b/examples/platforms/nrf528xx/src/flash.c
index 31d7af2ae..5282cd236 100644
--- a/examples/platforms/nrf528xx/src/flash.c
+++ b/examples/platforms/nrf528xx/src/flash.c
@@ -125,6 +125,8 @@ void otPlatFlashErase(otInstance *aInstance, uint8_t aSwapIndex)
         {
         }
     }
+
+    OT_UNUSED_VARIABLE(error);
 }
 
 void otPlatFlashWrite(otInstance *aInstance, uint8_t aSwapIndex, uint32_t aOffset, const void *aData, uint32_t aSize)
@@ -135,6 +137,8 @@ void otPlatFlashWrite(otInstance *aInstance, uint8_t aSwapIndex, uint32_t aOffse
 
     error = nrf5FlashWrite(mapAddress(aSwapIndex, aOffset), aData, aSize);
     assert(error == OT_ERROR_NONE);
+
+    OT_UNUSED_VARIABLE(error);
 }
 
 void otPlatFlashRead(otInstance *aInstance, uint8_t aSwapIndex, uint32_t aOffset, void *aData, uint32_t aSize)
diff --git a/examples/platforms/nrf528xx/src/transport/spi-slave.c b/examples/platforms/nrf528xx/src/transport/spi-slave.c
index fe4adc997..7738d62b1 100644
--- a/examples/platforms/nrf528xx/src/transport/spi-slave.c
+++ b/examples/platforms/nrf528xx/src/transport/spi-slave.c
@@ -148,6 +148,10 @@ otError otPlatSpiSlaveEnable(otPlatSpiSlaveTransactionCompleteCallback aComplete
 
     error = nrfx_spis_init(&sSpiSlaveInstance, &config, spisEventHandler, NULL);
     assert(error == NRFX_SUCCESS);
+    if (error != NRFX_SUCCESS)
+    {
+        result = OT_ERROR_FAILED;
+    }
 
     // Set up Host IRQ pin.
     nrf_gpio_pin_set(SPIS_PIN_HOST_IRQ);
diff --git a/examples/platforms/nrf528xx/src/transport/usb-cdc-uart.c b/examples/platforms/nrf528xx/src/transport/usb-cdc-uart.c
index 31e53a0b8..ec3a0060f 100644
--- a/examples/platforms/nrf528xx/src/transport/usb-cdc-uart.c
+++ b/examples/platforms/nrf528xx/src/transport/usb-cdc-uart.c
@@ -285,6 +285,8 @@ void nrf5UartInit(void)
 
     ret = app_usbd_power_events_enable();
     assert(ret == NRF_SUCCESS);
+
+    OT_UNUSED_VARIABLE(ret);
 }
 
 void nrf5UartDeinit(void)
diff --git a/script/check-arm-build-autotools b/script/check-arm-build-autotools
index ceebe1f8e..dee5ce31f 100755
--- a/script/check-arm-build-autotools
+++ b/script/check-arm-build-autotools
@@ -284,18 +284,28 @@ main()
 {
     ./bootstrap
 
-    build_cc1352
-    build_cc2538
-    build_cc2650
-    build_cc2652
-    build_jn5189
-    build_k32w061
-    build_kw41z
-    build_nrf52811
-    build_nrf52833
-    build_nrf52840
-    build_qpg6095
-    build_samr21
+    export CPPFLAGS="${CPPFLAGS:-} -DNDEBUG"
+
+    if [[ $# == 0 ]]; then
+        build_cc1352
+        build_cc2538
+        build_cc2650
+        build_cc2652
+        build_jn5189
+        build_k32w061
+        build_kw41z
+        build_nrf52811
+        build_nrf52833
+        build_nrf52840
+        build_qpg6095
+        build_samr21
+        return 0
+    fi
+
+    while [[ $# != 0 ]]; do
+        "build_$1"
+        shift
+    done
 }
 
 main "$@"
diff --git a/script/check-arm-build-cmake b/script/check-arm-build-cmake
index 0421e7721..5eddf856a 100755
--- a/script/check-arm-build-cmake
+++ b/script/check-arm-build-cmake
@@ -98,6 +98,8 @@ build_samr21()
 
 main()
 {
+    export CPPFLAGS="${CPPFLAGS:-} -DNDEBUG"
+
     if [[ $# == 0 ]]; then
         build_cc1352
         build_cc2538
diff --git a/third_party/NordicSemiconductor/Makefile.am b/third_party/NordicSemiconductor/Makefile.am
index b657ca174..998487be4 100644
--- a/third_party/NordicSemiconductor/Makefile.am
+++ b/third_party/NordicSemiconductor/Makefile.am
@@ -84,6 +84,9 @@ override CXXFLAGS := $(filter-out -Wundef,$(CXXFLAGS))
 override CFLAGS   := $(filter-out -Wcast-align,$(CFLAGS))
 override CXXFLAGS := $(filter-out -Wcast-align,$(CXXFLAGS))
 
+CFLAGS += -Wno-unused-but-set-variable
+CXXFLAGS += -Wno-unused-but-set-variable
+
 COMMONCPPFLAGS                                                                                                          = \
     -DCONFIG_GPIO_AS_PINRESET                                                                                             \
     -DENABLE_FEM=1                                                                                                        \
diff --git a/third_party/NordicSemiconductor/drivers/radio/mac_features/ack_generator/nrf_802154_ack_data.c b/third_party/NordicSemiconductor/drivers/radio/mac_features/ack_generator/nrf_802154_ack_data.c
index 2de5a213c..e4d449fd5 100644
--- a/third_party/NordicSemiconductor/drivers/radio/mac_features/ack_generator/nrf_802154_ack_data.c
+++ b/third_party/NordicSemiconductor/drivers/radio/mac_features/ack_generator/nrf_802154_ack_data.c
@@ -704,6 +704,7 @@ bool nrf_802154_ack_data_pending_bit_should_be_set(const uint8_t * p_frame)
 
         default:
             assert(false);
+            ret = false;
     }
 
     return ret;