diff --git a/src/command/handlers/cmd_piezo.c b/src/command/handlers/cmd_piezo.c
index b42e379..ff72876 100644
--- a/src/command/handlers/cmd_piezo.c
+++ b/src/command/handlers/cmd_piezo.c
@@ -38,8 +38,8 @@ int cmd_mbb(const uint8_t *data, uint8_t data_len)
 
     uint8_t session = cmd_next_echo_session();
 
-    int16_t accel[3];
-    int16_t gyro[3];
+    int16_t accel[3] = { (int16_t)0xFFFF, (int16_t)0xFFFF, (int16_t)0xFFFF };
+    int16_t gyro[3] = { (int16_t)0xFFFF, (int16_t)0xFFFF, (int16_t)0xFFFF };
 
     processing = true;
     DBG_PRINTF("[MBB] cmd start\r\n");
@@ -50,13 +50,29 @@ int cmd_mbb(const uint8_t *data, uint8_t data_len)
     /* Read battery first (idle measurement) so mbb? result matches msn? */
     DBG_PRINTF("[MBB] battery read (idle)\r\n");
     batt_mv = battery_read_mv();
+    if (batt_mv < 0)
+    {
+        DBG_PRINTF("[MBB] battery read fail\r\n");
+        batt_mv = 0xFFFF;
+    }
 
     int status = piezo_measure_start_session();
 
     if (status == ECHO_STATUS_OK) // Piezo GPIO, power, ADC initialization/wake succeeded
     {
         DBG_PRINTF("[MBB] imu/temp read\r\n");
-        imu_read_with_temperature(accel, gyro, &temp_cdeg);
+        int imu_ret = imu_read_with_temperature(accel, gyro, &temp_cdeg);
+        if (imu_ret != 0)
+        {
+            DBG_PRINTF("[MBB] imu/temp read fail ret=%d\r\n", imu_ret);
+            accel[0] = (int16_t)0xFFFF;
+            accel[1] = (int16_t)0xFFFF;
+            accel[2] = (int16_t)0xFFFF;
+            gyro[0] = (int16_t)0xFFFF;
+            gyro[1] = (int16_t)0xFFFF;
+            gyro[2] = (int16_t)0xFFFF;
+            temp_cdeg = (int16_t)0xFFFF;
+        }
 
         battery_protection_record_continuous(batt_mv, temp_cdeg); // update protection counters for continuous monitoring
 
@@ -240,8 +256,8 @@ int cmd_mim(const uint8_t *data, uint8_t data_len)
     int imu_ret = imu_fifo_start();
     if (imu_ret != 0)
     {
-        DBG_PRINTF("[MTB] fifo start fail ret=%d\r\n", imu_ret);
-        cmd_send_response_rim(tx_rim_samples, 0U);
+        DBG_PRINTF("[MIM] fifo start fail ret=%d\r\n", imu_ret);
+        cmd_send_response_rim_error();
         processing = false;
         return 1;
     }
@@ -252,7 +268,10 @@ int cmd_mim(const uint8_t *data, uint8_t data_len)
     if (imu_ret != 0)
     {
         DBG_PRINTF("[MIM] fifo read fail ret=%d\r\n", imu_ret);
-        rim_count = 0U;
+        cmd_send_response_rim_error();
+        imu_fifo_stop();
+        processing = false;
+        return 1;
     }
 
     cmd_send_response_rim(tx_rim_samples, rim_count); // IMU FIFO 15 samples rim: 전송