Dastels writes, “In my last post I described how I hacked a 2Mbyte SPI flash onto a Trinket M0 to give it the memory space for CircutiPython of one of the M0 Express boards. This time I supersized an M0 Express board, specifically a Feather M0 Express, although the same hack should work on a Circuit Playground Express.”
More details at Curmudgeoclast site.