diff --git a/conf/firmwares/subsystems/shared/imu_ardrone2.makefile b/conf/firmwares/subsystems/shared/imu_ardrone2.makefile
index ac06f5acf4..3a30478234 100644
--- a/conf/firmwares/subsystems/shared/imu_ardrone2.makefile
+++ b/conf/firmwares/subsystems/shared/imu_ardrone2.makefile
@@ -19,6 +19,8 @@ ap.srcs += $(imu_srcs)
 # Set the AHRS propegation frequencies
 AHRS_PROPAGATE_FREQUENCY ?= 200
 AHRS_CORRECT_FREQUENCY ?= 200
+ap.CFLAGS += -DAHRS_PROPAGATE_FREQUENCY=$(AHRS_PROPAGATE_FREQUENCY)
+ap.CFLAGS += -DAHRS_CORRECT_FREQUENCY=$(AHRS_CORRECT_FREQUENCY)
 
 #
 # Simulator