@subs Yes indeed! I was finding it difficult to get all of the controls working in Recalbox with both Pimoroni's original keyboard-oriented arduino board firmware as well as their self-configurable updated firmware. Whether I assigned custom keyboard or gamepad function mappings, the buttons never responded in games or the main menu--DESPITE being registered correctly during controller configuration in Recalbox.
I used the following custom firmware and everything works perfectly now.
Firmware:
https://github.com/DsChAeK/Picade
Pimoroni Forums Thread:
http://forums.pimoroni.com/t/another-alternate-firmware-for-the-retail-picade/916