diff --git a/src/modules/sensors/CMakeLists.txt b/src/modules/sensors/CMakeLists.txt
index e26df79246..a23f3c5341 100644
--- a/src/modules/sensors/CMakeLists.txt
+++ b/src/modules/sensors/CMakeLists.txt
@@ -37,7 +37,7 @@ px4_add_module(
 	PRIORITY "SCHED_PRIORITY_MAX-5"
 	STACK_MAIN 1300
 	COMPILE_FLAGS
-		-O3
+		-Os
 	SRCS
 		sensors.cpp
 		sensors_init.cpp