We received the prototypes little over a week ago. Though there were some issues with the PCB manufacturer as they used two of the wrong parts. The FPC connector they used is a bottom contact and we require a top contact, they used a latching switch instead of a momentary, and they didn't include the metal dome buttons. Really don't know how they used the wrong parts as I made sure to list every single part number and posted a link to a datasheet, I even did that to the 0 ohm resistors.
Another issues was that the reference schematic for the soft-shutdown was incorrect. The MOSFET's were mirrored (Source & Drain swapped). I should have caught that and a manual fix will need to be implemented on the current batch.
Software updates to utilize the MCP23S17 has been started. Check out the sample code here: https://github.com/davidperrenoud/gamegirl-joypad-MCP23S17
Kivutar has updated the lakka gamegirl image to the latest updates of LibreElec to support the Zero W wifi driver and added support to call a safe shutdown to the system through RetroArch to properly halt before shutdown 'echo -n "SHUTDOWN" | nc -u -w1 127.0.0.1 55355'.