diff --git a/EKF/RingBuffer.h b/EKF/RingBuffer.h
index c444075f1b..50c07a6985 100644
--- a/EKF/RingBuffer.h
+++ b/EKF/RingBuffer.h
@@ -37,6 +37,8 @@
  * Template RingBuffer.
  */
 
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include <cstdio>
 #include <cstring>
 
@@ -76,7 +78,7 @@ public:
 	inline void push(data_type sample, bool debug = false)
 	{
 		if (debug) {
-			printf("elapsed %llu\n", sample.time_us - _time_last);
+			printf("elapsed %" PRIu64 "\n", sample.time_us - _time_last);
 			_time_last = sample.time_us;
 		}
 
diff --git a/EKF/estimator_base.cpp b/EKF/estimator_base.cpp
index 5d3dede352..54a660a657 100644
--- a/EKF/estimator_base.cpp
+++ b/EKF/estimator_base.cpp
@@ -39,6 +39,8 @@
  *
  */
 
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
 #include <math.h>
 #include "estimator_base.h"
 #include <mathlib/mathlib.h>
@@ -381,7 +383,7 @@ void EstimatorBase::printStoredIMU()
 
 void EstimatorBase::printIMU(struct imuSample *data)
 {
-	printf("time %llu\n", data->time_us);
+	printf("time %" PRIu64 "\n", data->time_us);
 	printf("delta_ang_dt %.5f\n", (double)data->delta_ang_dt);
 	printf("delta_vel_dt %.5f\n", (double)data->delta_vel_dt);
 	printf("dA: %.5f %.5f %.5f \n", (double)data->delta_ang(0), (double)data->delta_ang(1), (double)data->delta_ang(2));
@@ -409,14 +411,14 @@ void EstimatorBase::printStoredMag()
 
 void EstimatorBase::printMag(struct magSample *data)
 {
-	printf("time %llu\n", data->time_us);
+	printf("time %" PRIu64 "\n", data->time_us);
 	printf("mag: %.5f %.5f %.5f \n\n", (double)data->mag(0), (double)data->mag(1), (double)data->mag(2));
 
 }
 
 void EstimatorBase::printBaro(struct baroSample *data)
 {
-	printf("time %llu\n", data->time_us);
+	printf("time %" PRIu64 "\n", data->time_us);
 	printf("baro: %.5f\n\n", (double)data->hgt);
 }
 
@@ -431,7 +433,7 @@ void EstimatorBase::printStoredBaro()
 
 void EstimatorBase::printGps(struct gpsSample *data)
 {
-	printf("time %llu\n", data->time_us);
+	printf("time %" PRIu64 "\n", data->time_us);
 	printf("gps pos: %.5f %.5f %.5f\n", (double)data->pos(0), (double)data->pos(1), (double)data->hgt);
 	printf("gps vel %.5f %.5f %.5f\n\n", (double)data->vel(0), (double)data->vel(1), (double)data->vel(2));
 }