We had reports on our repo that users were having issues with their Pico W locking up: pimoroni/pimoroni-pico#392

I can recreate this issue (using an M1 Macbook Air) with a very simple script:

import time
from machine import Pin

onboard = Pin("LED", Pin.OUT, value=0)

for i in range(0, 40000):
  onboard.on()
  time.sleep(0.025)
  onboard.off()
  time.sleep(0.025)

If that is saved as main.py then when the Pico starts up it will run for perhaps 20-30 iterations of the loop and then lock up hard every single time. Weirdly if I remotely execute the script using the mpremote tool then it runs flawlessly every time.

• occurs both with the official MicroPython build (currently rp2-pico-w-20220712-unstable-v1.19.1-127-g74794d42b.uf2) and also our build (pimoroni-picow-v1.19.2-micropython.uf2)
• definitely happens with MacOS (M1 specifically perhaps? not sure) but we think it may affect other platforms with less consistency
• does not occur on a Pico (sans wireless)
• does not occur if the device is plugged into a microB AC adaptor

I'm pretty sure something is causing the USB stack to fall over on the Pico W which is then causing it to hang completely.