diff --git a/src/firmware/nuttx/CMakeLists.txt b/src/firmware/nuttx/CMakeLists.txt
index be6f9b1062..649ce1e8fe 100644
--- a/src/firmware/nuttx/CMakeLists.txt
+++ b/src/firmware/nuttx/CMakeLists.txt
@@ -41,13 +41,17 @@ add_custom_target(check_weak
 
 if(NOT ${BOARD} STREQUAL "sim")
 
+	if (config_io_board)
+		set(extras "${CMAKE_BINARY_DIR}/src/modules/px4iofirmware/${config_io_board}.bin")
+	endif()
 
 	px4_nuttx_add_romfs(OUT romfs
 		ROOT ROMFS/px4fmu_common
-		EXTRAS ${CMAKE_BINARY_DIR}/src/modules/px4iofirmware/${config_io_board}.bin
+		EXTRAS ${extras}
 		)
-	add_dependencies(romfs fw_io)
-
+	if (config_io_board)
+	    add_dependencies(romfs fw_io)
+    endif()
 	set(fw_file
 		${CMAKE_CURRENT_BINARY_DIR}/${OS}-${BOARD}-${LABEL}.px4)