diff --git a/src/drivers/hmc5883/module.mk b/src/drivers/hmc5883/module.mk
index 5daa01dc57..be2ee72766 100644
--- a/src/drivers/hmc5883/module.mk
+++ b/src/drivers/hmc5883/module.mk
@@ -42,3 +42,5 @@ SRCS		= hmc5883.cpp
 MODULE_STACKSIZE	= 1200
 
 EXTRACXXFLAGS	= -Weffc++
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/l3gd20/module.mk b/src/drivers/l3gd20/module.mk
index 5630e7aeca..3d64d62be0 100644
--- a/src/drivers/l3gd20/module.mk
+++ b/src/drivers/l3gd20/module.mk
@@ -8,3 +8,5 @@ SRCS		 = l3gd20.cpp
 MODULE_STACKSIZE	= 1200
 
 EXTRACXXFLAGS	= -Weffc++
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/lsm303d/module.mk b/src/drivers/lsm303d/module.mk
index b4f3974f4d..0421eb113e 100644
--- a/src/drivers/lsm303d/module.mk
+++ b/src/drivers/lsm303d/module.mk
@@ -8,3 +8,5 @@ SRCS		 = lsm303d.cpp
 MODULE_STACKSIZE	= 1200
 
 EXTRACXXFLAGS	= -Weffc++
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/mpu6000/module.mk b/src/drivers/mpu6000/module.mk
index 5b4893b127..da9fcc0fc4 100644
--- a/src/drivers/mpu6000/module.mk
+++ b/src/drivers/mpu6000/module.mk
@@ -42,3 +42,5 @@ SRCS		= mpu6000.cpp
 MODULE_STACKSIZE	= 1200
 
 EXTRACXXFLAGS	= -Weffc++
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/px4io/module.mk b/src/drivers/px4io/module.mk
index 5b838fb75e..924283356b 100644
--- a/src/drivers/px4io/module.mk
+++ b/src/drivers/px4io/module.mk
@@ -48,3 +48,5 @@ INCLUDE_DIRS    += $(NUTTX_SRC)/arch/arm/src/stm32 $(NUTTX_SRC)/arch/arm/src/com
 MODULE_STACKSIZE = 1200
 
 EXTRACXXFLAGS	= -Weffc++
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/modules/bottle_drop/module.mk b/src/modules/bottle_drop/module.mk
index 6b18fff556..9602288790 100644
--- a/src/modules/bottle_drop/module.mk
+++ b/src/modules/bottle_drop/module.mk
@@ -39,3 +39,5 @@ MODULE_COMMAND		= bottle_drop
 
 SRCS			= bottle_drop.cpp \
 			  bottle_drop_params.c
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/modules/sdlog2/module.mk b/src/modules/sdlog2/module.mk
index a28d43e725..d4a00af39d 100644
--- a/src/modules/sdlog2/module.mk
+++ b/src/modules/sdlog2/module.mk
@@ -43,3 +43,5 @@ SRCS = sdlog2.c \
        logbuffer.c
 
 MODULE_STACKSIZE = 1200
+
+MAXOPTIMIZATION	 = -Os