I'm using version 3.5.0a of PlatformIO. Sketches I build (Blinky to start) for a couple Adafruit Feather M0 boards upload successfully but do not run. Building the same code in Arduino IDE 1.8.1 loads and runs fine.
I'm using the following in platformio.ini
platform = atmelsam
board = adafruit_feather_m0
framework = arduino
bossac output from each upload (PIO and Arduino IDE) look identical.
Any ideas about how to investigate the problem?