diff --git a/src/drivers/px4fmu/module.mk b/src/drivers/px4fmu/module.mk
index a60f1a434a..a06323a52f 100644
--- a/src/drivers/px4fmu/module.mk
+++ b/src/drivers/px4fmu/module.mk
@@ -8,3 +8,5 @@ SRCS		 = fmu.cpp
 MODULE_STACKSIZE = 1200
 
 EXTRACXXFLAGS	= -Weffc++
+
+MAXOPTIMIZATION	 = -Os