diff --git a/configs/nucleo-l452re/src/stm32_adc.c b/configs/nucleo-l452re/src/stm32_adc.c
index b12471e49b..dde6eb3618 100644
--- a/configs/nucleo-l452re/src/stm32_adc.c
+++ b/configs/nucleo-l452re/src/stm32_adc.c
@@ -168,7 +168,8 @@ int stm32l4_adc_measure_voltages(uint32_t *vrefint, uint32_t *vbat, uint32_t *ve
   ssize_t nbytes;
   struct adc_msg_s sample[ADC1_NCHANNELS] = { 0 };
   int nsamples;
-  int fd, ret, errval;
+  int ret;
+  int fd;
 
   fd = open("/dev/adc0", O_RDONLY);
   if (fd < 0)
@@ -245,6 +246,7 @@ int stm32l4_adc_measure_voltages(uint32_t *vrefint, uint32_t *vbat, uint32_t *ve
                 tsense = (110 - 30) * (sample[i].am_data - STM32_TSENSE_TSCAL1)
                                     / (STM32_TSENSE_TSCAL2 - STM32_TSENSE_TSCAL1) + 30;
                 ainfo("TSENSE: %d -> %d °C\n", sample[i].am_data, tsense);
+                UNUSED(tsense);
                 break;
 
               case ADC1_INTERNAL_VBATDIV3_CHANNEL:
diff --git a/configs/nucleo-l452re/src/stm32_bringup.c b/configs/nucleo-l452re/src/stm32_bringup.c
index 1eed61443a..571a15fa0c 100644
--- a/configs/nucleo-l452re/src/stm32_bringup.c
+++ b/configs/nucleo-l452re/src/stm32_bringup.c
@@ -43,7 +43,12 @@
 #include <sys/types.h>
 #include <debug.h>
 
+#include <nuttx/input/buttons.h>
 #include <nuttx/i2c/i2c_master.h>
+#include <nuttx/leds/userled.h>
+#include <nuttx/board.h>
+
+#include <arch/board/board.h>
 
 #include "stm32l4_i2c.h"
 #include "nucleo-l452re.h"
@@ -92,6 +97,24 @@ int stm32_bringup(void)
     }
 #endif
 
+#ifdef CONFIG_BUTTONS
+#ifdef CONFIG_BUTTONS_LOWER
+  iinfo("Initializing button driver\n");
+
+  /* Register the BUTTON driver */
+
+  ret = btn_lower_initialize("/dev/buttons");
+  if (ret < 0)
+    {
+      ierr("ERROR: btn_lower_initialize() failed: %d\n", ret);
+    }
+#else
+  /* Enable BUTTON support for some other purpose */
+
+  board_button_initialize();
+#endif
+#endif /* CONFIG_BUTTONS */
+
 #ifdef HAVE_I2C_DRIVER
   /* Get the I2C lower half instance */