Also compile iofirmware and use it

I am trying to also build the iofirmware and use it in Arducopter.
For only building Arducopter I use: ./waf --targets bin/arducopter
For also building iofirmware I use: ./waf iofirmware --targets bin/arducopter
But this gives error “Group iofirmware not found”
What is the proper way to build the iofirmware and then use it during the update? I tried to find any related topic, but not found…
Thanks a lot!!!

What is a "io"firmware ? Can you tell me know more about this feature.

Thank you :slightly_smiling_face: