diff --git a/src/drivers/aerofc_adc/CMakeLists.txt b/src/drivers/aerofc_adc/CMakeLists.txt
index 2bb86d84c6..4b1a6cd2ae 100644
--- a/src/drivers/aerofc_adc/CMakeLists.txt
+++ b/src/drivers/aerofc_adc/CMakeLists.txt
@@ -34,7 +34,6 @@ px4_add_module(
 	MODULE drivers__aerofc_adc
 	MAIN aerofc_adc
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		aerofc_adc.cpp
 	DEPENDS
diff --git a/src/drivers/boards/esc35-v1/CMakeLists.txt b/src/drivers/boards/esc35-v1/CMakeLists.txt
index 4ec4ee7184..285901af92 100644
--- a/src/drivers/boards/esc35-v1/CMakeLists.txt
+++ b/src/drivers/boards/esc35-v1/CMakeLists.txt
@@ -70,7 +70,6 @@ endif()
 px4_add_module(
 	MODULE drivers__boards__esc35-v1
 	COMPILE_FLAGS
-		-Os
 	SRCS ${SRCS}
 	DEPENDS
 		platforms__common
diff --git a/src/drivers/boards/esc35-v1/bootloader/CMakeLists.txt b/src/drivers/boards/esc35-v1/bootloader/CMakeLists.txt
index ce5446fe80..710bba55b3 100644
--- a/src/drivers/boards/esc35-v1/bootloader/CMakeLists.txt
+++ b/src/drivers/boards/esc35-v1/bootloader/CMakeLists.txt
@@ -45,7 +45,6 @@ include_directories(.)
 px4_add_module(
 	MODULE drivers__boards__esc35-v1__bootloader
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		boot.c
 		led.c
diff --git a/src/drivers/boards/px4cannode-v1/CMakeLists.txt b/src/drivers/boards/px4cannode-v1/CMakeLists.txt
index b888a5f24a..a1b52f1949 100644
--- a/src/drivers/boards/px4cannode-v1/CMakeLists.txt
+++ b/src/drivers/boards/px4cannode-v1/CMakeLists.txt
@@ -64,7 +64,6 @@ endif()
 px4_add_module(
 	MODULE drivers__boards__px4cannode-v1
 	COMPILE_FLAGS
-		-Os
 	SRCS ${SRCS}
 	DEPENDS
 		platforms__common
diff --git a/src/drivers/boards/px4cannode-v1/bootloader/CMakeLists.txt b/src/drivers/boards/px4cannode-v1/bootloader/CMakeLists.txt
index 3fc8e1ea7c..09a101560c 100644
--- a/src/drivers/boards/px4cannode-v1/bootloader/CMakeLists.txt
+++ b/src/drivers/boards/px4cannode-v1/bootloader/CMakeLists.txt
@@ -45,7 +45,6 @@ include_directories(.)
 px4_add_module(
 	MODULE drivers__boards__px4cannode-v1__bootloader
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		boot.c
 		led.c
diff --git a/src/drivers/boards/px4esc-v1/CMakeLists.txt b/src/drivers/boards/px4esc-v1/CMakeLists.txt
index 190a1ee5fb..c776a8d1e9 100644
--- a/src/drivers/boards/px4esc-v1/CMakeLists.txt
+++ b/src/drivers/boards/px4esc-v1/CMakeLists.txt
@@ -62,7 +62,6 @@ endif()
 px4_add_module(
 	MODULE drivers__boards__px4esc-v1
 	COMPILE_FLAGS
-		-Os
 	SRCS ${SRCS}
 	DEPENDS
 		platforms__common
diff --git a/src/drivers/boards/px4esc-v1/bootloader/CMakeLists.txt b/src/drivers/boards/px4esc-v1/bootloader/CMakeLists.txt
index a2bc84546f..06f6d89e4b 100644
--- a/src/drivers/boards/px4esc-v1/bootloader/CMakeLists.txt
+++ b/src/drivers/boards/px4esc-v1/bootloader/CMakeLists.txt
@@ -45,7 +45,6 @@ include_directories(.)
 px4_add_module(
 	MODULE drivers__boards__px4esc-v1__bootloader
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		boot.c
 		led.c
diff --git a/src/drivers/boards/px4flow-v2/CMakeLists.txt b/src/drivers/boards/px4flow-v2/CMakeLists.txt
index e748ff2108..def01316f6 100644
--- a/src/drivers/boards/px4flow-v2/CMakeLists.txt
+++ b/src/drivers/boards/px4flow-v2/CMakeLists.txt
@@ -62,7 +62,6 @@ endif()
 px4_add_module(
 	MODULE drivers__boards__px4flow-v2
 	COMPILE_FLAGS
-		-Os
 	SRCS ${SRCS}
 	DEPENDS
 		platforms__common
diff --git a/src/drivers/boards/px4flow-v2/bootloader/CMakeLists.txt b/src/drivers/boards/px4flow-v2/bootloader/CMakeLists.txt
index ba4c88e0a9..de789e83fc 100644
--- a/src/drivers/boards/px4flow-v2/bootloader/CMakeLists.txt
+++ b/src/drivers/boards/px4flow-v2/bootloader/CMakeLists.txt
@@ -45,7 +45,6 @@ include_directories(.)
 px4_add_module(
 	MODULE drivers__boards__px4flow-v2__bootloader
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		boot.c
 		led.c
diff --git a/src/drivers/boards/px4fmu-v5/CMakeLists.txt b/src/drivers/boards/px4fmu-v5/CMakeLists.txt
index 27472134e9..ea0f6cb143 100644
--- a/src/drivers/boards/px4fmu-v5/CMakeLists.txt
+++ b/src/drivers/boards/px4fmu-v5/CMakeLists.txt
@@ -33,7 +33,6 @@
 px4_add_module(
 	MODULE drivers__boards__px4fmu-v5
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		../common/stm32/board_reset.c
 		../common/stm32/board_identity.c
diff --git a/src/drivers/boards/px4nucleoF767ZI-v1/CMakeLists.txt b/src/drivers/boards/px4nucleoF767ZI-v1/CMakeLists.txt
index ff83bc4aaa..3f1618aaa1 100644
--- a/src/drivers/boards/px4nucleoF767ZI-v1/CMakeLists.txt
+++ b/src/drivers/boards/px4nucleoF767ZI-v1/CMakeLists.txt
@@ -33,7 +33,6 @@
 px4_add_module(
 	MODULE drivers__boards__px4nucleoF767ZI-v1
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		../common/stm32/board_reset.c
 		../common/stm32/board_identity.c
diff --git a/src/drivers/boards/s2740vc-v1/CMakeLists.txt b/src/drivers/boards/s2740vc-v1/CMakeLists.txt
index cc2762001a..0f5502d542 100644
--- a/src/drivers/boards/s2740vc-v1/CMakeLists.txt
+++ b/src/drivers/boards/s2740vc-v1/CMakeLists.txt
@@ -70,7 +70,6 @@ endif()
 px4_add_module(
 	MODULE drivers__boards__s2740vc-v1
 	COMPILE_FLAGS
-		-Os
 	SRCS ${SRCS}
 	DEPENDS
 		platforms__common
diff --git a/src/drivers/boards/s2740vc-v1/bootloader/CMakeLists.txt b/src/drivers/boards/s2740vc-v1/bootloader/CMakeLists.txt
index b64e87ddc9..a6a15bf9b3 100644
--- a/src/drivers/boards/s2740vc-v1/bootloader/CMakeLists.txt
+++ b/src/drivers/boards/s2740vc-v1/bootloader/CMakeLists.txt
@@ -45,7 +45,6 @@ include_directories(.)
 px4_add_module(
 	MODULE drivers__boards__s2740vc-v1__bootloader
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		boot.c
 		../../common/stm32/board_identity.c
diff --git a/src/drivers/boards/zubaxgnss-v1/CMakeLists.txt b/src/drivers/boards/zubaxgnss-v1/CMakeLists.txt
index 3864afaa9b..3a96116a3a 100644
--- a/src/drivers/boards/zubaxgnss-v1/CMakeLists.txt
+++ b/src/drivers/boards/zubaxgnss-v1/CMakeLists.txt
@@ -61,7 +61,6 @@ endif()
 px4_add_module(
 	MODULE drivers__boards__zubaxgnss-v1
 	COMPILE_FLAGS
-		-Os
 	SRCS ${SRCS}
 	DEPENDS
 		platforms__common
diff --git a/src/drivers/boards/zubaxgnss-v1/bootloader/CMakeLists.txt b/src/drivers/boards/zubaxgnss-v1/bootloader/CMakeLists.txt
index 00b61ce1bf..963e761748 100644
--- a/src/drivers/boards/zubaxgnss-v1/bootloader/CMakeLists.txt
+++ b/src/drivers/boards/zubaxgnss-v1/bootloader/CMakeLists.txt
@@ -45,7 +45,6 @@ include_directories(.)
 px4_add_module(
 	MODULE drivers__boards__zubaxgnss-v1__bootloader
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		boot.c
 		led.c
diff --git a/src/drivers/iridiumsbd/CMakeLists.txt b/src/drivers/iridiumsbd/CMakeLists.txt
index 25dba0502b..a67a04e796 100644
--- a/src/drivers/iridiumsbd/CMakeLists.txt
+++ b/src/drivers/iridiumsbd/CMakeLists.txt
@@ -36,7 +36,6 @@ px4_add_module(
 	STACK 1024
 	STACK_MAIN 1024
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		IridiumSBD.cpp
 		iridiumsbd_params.c
diff --git a/src/drivers/ist8310/CMakeLists.txt b/src/drivers/ist8310/CMakeLists.txt
index 67d2d59f8f..fda529310d 100644
--- a/src/drivers/ist8310/CMakeLists.txt
+++ b/src/drivers/ist8310/CMakeLists.txt
@@ -35,7 +35,6 @@ px4_add_module(
 	MAIN ist8310
 	STACK_MAIN 1200
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		ist8310.cpp
 	DEPENDS
diff --git a/src/drivers/ulanding/CMakeLists.txt b/src/drivers/ulanding/CMakeLists.txt
index 73f5d3580b..4575df9cf9 100644
--- a/src/drivers/ulanding/CMakeLists.txt
+++ b/src/drivers/ulanding/CMakeLists.txt
@@ -34,7 +34,6 @@ px4_add_module(
 	MODULE drivers__ulanding
 	MAIN ulanding_radar
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		ulanding.cpp
 	DEPENDS
diff --git a/src/modules/uavcanesc/nshterm/CMakeLists.txt b/src/modules/uavcanesc/nshterm/CMakeLists.txt
index 9a6ffc82c4..c3362d12f3 100644
--- a/src/modules/uavcanesc/nshterm/CMakeLists.txt
+++ b/src/modules/uavcanesc/nshterm/CMakeLists.txt
@@ -37,7 +37,6 @@ px4_add_module(
 	STACK_MAIN 1500
 	COMPILE_FLAGS
 		-Wno-deprecated-declarations
-		-Os
 	SRCS
 	 nshterm.c
     PRIORITY "SCHED_PRIORITY_DEFAULT-30"
diff --git a/src/systemcmds/hardfault_log/CMakeLists.txt b/src/systemcmds/hardfault_log/CMakeLists.txt
index f275b98942..b5e768a18f 100644
--- a/src/systemcmds/hardfault_log/CMakeLists.txt
+++ b/src/systemcmds/hardfault_log/CMakeLists.txt
@@ -35,7 +35,6 @@ px4_add_module(
 	MAIN hardfault_log
 	STACK_MAIN 2048
 	COMPILE_FLAGS
-		-Os
 	SRCS
 		hardfault_log.c
 	DEPENDS