Received two prototype (populated) boards in post. Preliminary test went well, everything appear correct, including the code for the new 6 x 17 matrix layout as opposed to the 10 x10 matrix used in my original Blackpill keyboard.

I failed to notice that QMK supports 25xx-series for SPI (and 24xx-series for IC2) so the current test EEPROM footprint needs changing.

As noted earlier, the new dev board are designed to use a 6 x 17 matrix and the QMK keyboard files require updates to reflect this. After updates to the code, the keyboard generate the correct codes but the layout in usevia.app needs a little work, the Enter key is not in the correct position ++