diff --git a/Tools/ardupilotwaf/boards.py b/Tools/ardupilotwaf/boards.py
index 7ff8a70016..b8fcb0eb44 100644
--- a/Tools/ardupilotwaf/boards.py
+++ b/Tools/ardupilotwaf/boards.py
@@ -225,6 +225,14 @@ class Board:
     def embed_ROMFS_files(self, ctx):
         '''embed some files using AP_ROMFS'''
         import embed
+        if ctx.env.USE_NUTTX_IOFW:
+            # use fmuv2_IO_NuttX.bin instead of fmuv2_IO.bin
+            for i in range(len(ctx.env.ROMFS_FILES)):
+                (name,filename) = ctx.env.ROMFS_FILES[i]
+                if name == 'io_firmware.bin':
+                    filename = 'Tools/IO_Firmware/fmuv2_IO_NuttX.bin'
+                    print("Using IO firmware %s" % filename)
+                    ctx.env.ROMFS_FILES[i] = (name,filename);
         header = ctx.bldnode.make_node('ap_romfs_embedded.h').abspath()
         if not embed.create_embedded_h(header, ctx.env.ROMFS_FILES):
             bld.fatal("Failed to created ap_romfs_embedded.h")
diff --git a/wscript b/wscript
index b5f3714d2e..d7144d6276 100644
--- a/wscript
+++ b/wscript
@@ -71,6 +71,11 @@ def options(opt):
         action='store_true',
         default=False,
         help='enable OS level asserts.')
+
+    g.add_option('--use-nuttx-iofw',
+        action='store_true',
+        default=False,
+        help='use old NuttX IO firmware for IOMCU')
     
     g.add_option('--bootloader',
         action='store_true',
@@ -193,6 +198,7 @@ def configure(cfg):
     cfg.env.DEBUG = cfg.options.debug
     cfg.env.ENABLE_ASSERTS = cfg.options.enable_asserts
     cfg.env.BOOTLOADER = cfg.options.bootloader
+    cfg.env.USE_NUTTX_IOFW = cfg.options.use_nuttx_iofw
 
     # Allow to differentiate our build from the make build
     cfg.define('WAF_BUILD', 1)