diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_BMI160.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_BMI160.cpp
index 94ee571b11..9b0c405fe0 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_BMI160.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_BMI160.cpp
@@ -152,7 +152,7 @@ void AP_InertialSensor_BMI160::start()
 {
     bool r;
 
-    if (!_dev->get_semaphore()->take(0)) {
+    if (!_dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
         return;
     }
 
@@ -428,7 +428,7 @@ bool AP_InertialSensor_BMI160::_hardware_init()
 
     hal.scheduler->delay(BMI160_POWERUP_DELAY_MSEC);
 
-    if (!_dev->get_semaphore()->take(0)) {
+    if (!_dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
         return false;
     }
 
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_Backend.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_Backend.cpp
index 9d29e65048..967486b985 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_Backend.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_Backend.cpp
@@ -97,7 +97,7 @@ void AP_InertialSensor_Backend::_notify_new_gyro_raw_sample(uint8_t instance,
     delta_coning = delta_coning % delta_angle;
     delta_coning *= 0.5f;
 
-    if (_sem->take(0)) {
+    if (_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
         // integrate delta angle accumulator
         // the angles and coning corrections are accumulated separately in the
         // referenced paper, but in simulation little difference was found between
@@ -187,7 +187,7 @@ void AP_InertialSensor_Backend::_notify_new_accel_raw_sample(uint8_t instance,
     
     _imu.calc_vibration_and_clipping(instance, accel, dt);
 
-    if (_sem->take(0)) {
+    if (_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
         // delta velocity
         _imu._delta_velocity_acc[instance] += accel * dt;
         _imu._delta_velocity_acc_dt[instance] += dt;
@@ -273,7 +273,7 @@ void AP_InertialSensor_Backend::_publish_temperature(uint8_t instance, float tem
  */
 void AP_InertialSensor_Backend::update_gyro(uint8_t instance)
 {    
-    if (!_sem->take(0)) {
+    if (!_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
         return;
     }
 
@@ -296,7 +296,7 @@ void AP_InertialSensor_Backend::update_gyro(uint8_t instance)
  */
 void AP_InertialSensor_Backend::update_accel(uint8_t instance)
 {    
-    if (!_sem->take(0)) {
+    if (!_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
         return;
     }
 
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_Invensense.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_Invensense.cpp
index 51775cfa20..e011128dee 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_Invensense.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_Invensense.cpp
@@ -372,7 +372,7 @@ bool AP_InertialSensor_Invensense::_has_auxiliary_bus()
 
 void AP_InertialSensor_Invensense::start()
 {
-    if (!_dev->get_semaphore()->take(0)) {
+    if (!_dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
         return;
     }
 
@@ -825,7 +825,7 @@ bool AP_InertialSensor_Invensense::_check_whoami(void)
 
 bool AP_InertialSensor_Invensense::_hardware_init(void)
 {
-    if (!_dev->get_semaphore()->take(0)) {
+    if (!_dev->get_semaphore()->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
         return false;
     }