I received the boards and they passed the smoke test.  Great job MacroFab!

It didn't take too long to get the uf2-samdx1 bootloader running on it:

https://github.com/gsteiert/uf2-samdx1/tree/fpga-helper

I started working on circuitpython and seesaw ports, but those will take a bit more time.  For now I will focus on the basic uf2 interface to the SPI flash.