diff --git a/sw/airborne/arch/sim/subsystems/imu/imu_b2_arch.c b/sw/airborne/arch/sim/subsystems/imu/imu_b2_arch.c
index a8035a810f..e486ebbc38 100644
--- a/sw/airborne/arch/sim/subsystems/imu/imu_b2_arch.c
+++ b/sw/airborne/arch/sim/subsystems/imu/imu_b2_arch.c
@@ -25,6 +25,8 @@
 
 #include "generated/airframe.h"
 
+int imu_overrun = 0;
+
 void imu_b2_arch_init(void) {
 
 }
diff --git a/sw/airborne/arch/sim/subsystems/imu/imu_b2_arch.h b/sw/airborne/arch/sim/subsystems/imu/imu_b2_arch.h
index 568e75a51f..8ef38139af 100644
--- a/sw/airborne/arch/sim/subsystems/imu/imu_b2_arch.h
+++ b/sw/airborne/arch/sim/subsystems/imu/imu_b2_arch.h
@@ -29,6 +29,7 @@
 #ifndef IMU_B2_ARCH_H
 #define IMU_B2_ARCH_H
 
+extern int imu_overrun;
 
 extern void imu_feed_gyro_accel(void);
 extern void imu_feed_mag(void);