bl_update: build and include board bootloader if config available

src/systemcmds/bl_update/CMakeLists.txt

@@ -38,4 +38,43 @@ px4_add_module(
 		-Wno-cast-align # TODO: fix and enable
 	SRCS
 		bl_update.c
+)
+
+if(config_build_bootloader)
+	# include the bootloader binary in ROMFS
+	set(bootloader_config "${PX4_BOARD_VENDOR}_${PX4_BOARD_MODEL}_bootloader")
+
+	if(NOT EXISTS ${PX4_BOARD_DIR}/nuttx-config/bootloader)
+		message(FATAL_ERROR "${bootloader_config} does not exist")
+	endif()
+
+	message(STATUS "Building and including bootloader ${bootloader_config}")
+
+	include(ExternalProject)
+	ExternalProject_Add(bootloader_firmware
+		SOURCE_DIR ${CMAKE_SOURCE_DIR}
+		DOWNLOAD_COMMAND ""
+		UPDATE_COMMAND ""
+		CMAKE_ARGS -DCONFIG=${bootloader_config}
+		INSTALL_COMMAND ""
+		USES_TERMINAL_BUILD true
+		DEPENDS git_nuttx git_nuttx_apps
+		BUILD_ALWAYS 1
 	)
+
+	ExternalProject_Get_Property(bootloader_firmware BINARY_DIR)
+
+	set(bootloader_exe "${BINARY_DIR}/${bootloader_config}.elf")
+	set(bootloader_bin "${PX4_BINARY_DIR}/romfs_extras/${bootloader_config}.bin" CACHE FILEPATH "bootloader binary path")
+
+	file(RELATIVE_PATH bootloader_exe_relative ${CMAKE_CURRENT_BINARY_DIR} ${bootloader_exe})
+	file(RELATIVE_PATH bootloader_bin_relative ${CMAKE_CURRENT_BINARY_DIR} ${bootloader_bin})
+
+	add_custom_command(OUTPUT ${bootloader_bin}
+		COMMAND ${CMAKE_COMMAND} -E make_directory ${PX4_BINARY_DIR}/romfs_extras
+		COMMAND ${CMAKE_OBJCOPY} -O binary ${bootloader_exe_relative} ${bootloader_bin_relative}
+		DEPENDS bootloader_firmware
+		COMMENT "Copying ${bootloader_config} to ROMFS extras"
+		)
+	add_custom_target(copy_bootloader_bin DEPENDS ${bootloader_bin})
+endif()