diff --git a/ROMFS/CMakeLists.txt b/ROMFS/CMakeLists.txt
index 3a7def2633..0709608ac2 100644
--- a/ROMFS/CMakeLists.txt
+++ b/ROMFS/CMakeLists.txt
@@ -78,7 +78,12 @@ file(GLOB jinja_templates ${PX4_SOURCE_DIR}/Tools/serial/*.jinja)
 if (px4_constrained_flash_build)
 	set(added_arguments --constrained-flash)
 endif()
-add_custom_command(OUTPUT ${romfs_gen_root_dir}/init.d/rcS ${romfs_gen_root_dir}/init.d/rc.serial ${romfs_gen_root_dir}/init.d/rc.autostart
+add_custom_command(
+	OUTPUT
+		${romfs_gen_root_dir}/init.d/rcS
+		${romfs_gen_root_dir}/init.d/rc.serial
+		${romfs_gen_root_dir}/init.d/rc.autostart
+		romfs_copy.stamp
 	COMMAND ${CMAKE_COMMAND} -E remove_directory ${romfs_gen_root_dir}
 	# TODO: we should only copy the files in ${romfs_copy_files}
 	COMMAND ${CMAKE_COMMAND} -E copy_directory ${romfs_src_dir} ${romfs_gen_root_dir}
@@ -95,6 +100,7 @@ add_custom_command(OUTPUT ${romfs_gen_root_dir}/init.d/rcS ${romfs_gen_root_dir}
 		--rc-dir ${romfs_gen_root_dir}/init.d
 		--serial-ports ${board_serial_ports} ${added_arguments}
 		--config-files ${module_config_files} #--verbose
+	COMMAND ${CMAKE_COMMAND} -E touch romfs_copy.stamp
 	DEPENDS
 		${jinja_templates}
 		${module_config_files}
@@ -138,16 +144,20 @@ foreach(board_rc_file ${OPTIONAL_BOARD_RC})
 	if(EXISTS "${PX4_BOARD_DIR}/init/${board_rc_file}")
 		message(STATUS "ROMFS: Adding ${board_rc_file}")
 
-		add_custom_command(OUTPUT ${romfs_gen_root_dir}/init.d/${board_rc_file}
+		add_custom_command(
+			OUTPUT
+				${romfs_gen_root_dir}/init.d/${board_rc_file}
+				${board_rc_file}.stamp
 			COMMAND ${CMAKE_COMMAND} -E copy ${PX4_BOARD_DIR}/init/${board_rc_file} ${romfs_gen_root_dir}/init.d/${board_rc_file}
+			COMMAND ${CMAKE_COMMAND} -E touch ${board_rc_file}.stamp
 			DEPENDS
 				${PX4_BOARD_DIR}/init/${board_rc_file}
-				${romfs_gen_root_dir}/init.d/rcS
+				romfs_copy.stamp
 			COMMENT "ROMFS: copying ${board_rc_file}"
 		)
 
 		list(APPEND extras_dependencies
-			${romfs_gen_root_dir}/init.d/${board_rc_file}
+			${board_rc_file}.stamp
 			)
 	endif()
 
@@ -159,8 +169,7 @@ add_custom_command(OUTPUT romfs_extras.stamp
 	COMMAND ${CMAKE_COMMAND} -E copy_directory ${PX4_BINARY_DIR}/romfs_extras/ ${romfs_gen_root_dir}/extras/
 	COMMAND ${CMAKE_COMMAND} -E touch romfs_extras.stamp
 	DEPENDS
-		${romfs_gen_root_dir}/init.d/rcS
-		${romfs_gen_root_dir}/init.d/rc.autostart
+		romfs_copy.stamp
 		${extras_dependencies}
 	COMMENT "ROMFS: copying extras"
 	)
@@ -170,8 +179,7 @@ add_custom_command(
 	COMMAND ${PYTHON_EXECUTABLE} ${PX4_SOURCE_DIR}/Tools/px_romfs_pruner.py --folder ${romfs_gen_root_dir} --board ${PX4_BOARD}
 	COMMAND ${CMAKE_COMMAND} -E touch romfs_pruned.stamp
 	DEPENDS
-		${romfs_gen_root_dir}/init.d/rcS
-		${romfs_gen_root_dir}/init.d/rc.autostart
+		romfs_copy.stamp
 		romfs_extras.stamp
 		${PX4_SOURCE_DIR}/Tools/px_romfs_pruner.py
 	COMMENT "ROMFS: pruning"
@@ -184,7 +192,7 @@ if("${CONFIG_FS_CROMFS}" STREQUAL "y")
 		COMMAND ${CMAKE_COMMAND} -E copy gencromfs ${CMAKE_BINARY_DIR}/gencromfs
 		DEPENDS ${PX4_SOURCE_DIR}/platforms/nuttx/NuttX/nuttx/tools/gencromfs.c
 		WORKING_DIRECTORY ${NUTTX_DIR}/tools
-		)
+	)
 
 	# create nsh_romfsimg.c
 	add_custom_command(OUTPUT nsh_romfsimg.c
@@ -192,37 +200,45 @@ if("${CONFIG_FS_CROMFS}" STREQUAL "y")
 		COMMAND ${CMAKE_BINARY_DIR}/gencromfs ${romfs_gen_root_dir} nsh_romfsimg.c
 		DEPENDS
 			${CMAKE_BINARY_DIR}/gencromfs
-			${romfs_gen_root_dir}/init.d/rcS
-			${romfs_gen_root_dir}/init.d/rc.autostart
-			romfs_extras.stamp
 			romfs_pruned.stamp
 		COMMENT "ROMFS: generating image"
-		)
+	)
 
 else()
 	# create romfs.img
 	find_program(GENROMFS genromfs)
 	if(NOT GENROMFS)
-	    message(FATAL_ERROR "genromfs not found")
+		message(FATAL_ERROR "genromfs not found")
 	endif()
-	add_custom_command(OUTPUT romfs.img romfs.txt
+
+	add_custom_command(
+		OUTPUT
+			romfs.img
+			romfs.txt
 		COMMAND ${CMAKE_COMMAND} -E remove -f romfs.img romfs.txt
 		COMMAND ${GENROMFS} -f romfs.img -d ${romfs_gen_root_dir} -V "NSHInitVol" -v > romfs.txt 2>&1
 		DEPENDS romfs_pruned.stamp
 		COMMENT "ROMFS: generating image"
-		)
+	)
 
-		# create nsh_romfsimg.c
-		find_program(XXD xxd)
-		if(NOT XXD)
-		    message(FATAL_ERROR "xxd not found")
-		endif()
-		add_custom_command(OUTPUT nsh_romfsimg.c
-			COMMAND ${CMAKE_COMMAND} -E remove -f nsh_romfsimg.c
-			COMMAND ${XXD} -i romfs.img nsh_romfsimg.c
-			COMMAND sed 's/unsigned/const unsigned/g' nsh_romfsimg.c > nsh_romfsimg.c.tmp && ${CMAKE_COMMAND} -E rename nsh_romfsimg.c.tmp nsh_romfsimg.c
-			DEPENDS romfs.img
-			)
+
+	# create nsh_romfsimg.c
+	find_program(XXD xxd)
+	if(NOT XXD)
+		message(FATAL_ERROR "xxd not found")
+	endif()
+
+	find_program(SED sed)
+	if(NOT SED)
+		message(FATAL_ERROR "sed not found")
+	endif()
+
+	add_custom_command(OUTPUT nsh_romfsimg.c
+		COMMAND ${CMAKE_COMMAND} -E remove -f nsh_romfsimg.c
+		COMMAND ${XXD} -i romfs.img nsh_romfsimg.c
+		COMMAND ${SED} 's/unsigned/const unsigned/g' nsh_romfsimg.c > nsh_romfsimg.c.tmp && ${CMAKE_COMMAND} -E rename nsh_romfsimg.c.tmp nsh_romfsimg.c
+		DEPENDS romfs.img
+	)
 endif()
 
 
@@ -248,5 +264,5 @@ if(SHELLCHECK_PATH)
 		DEPENDS ${romfs_gen_root_dir}/init.d/rc.autostart
 		WORKING_DIRECTORY ${romfs_gen_root_dir}
 		USES_TERMINAL
-    )
+	)
 endif()