@hathach This might be a good lead on some USB issues, and one you could test locally.

@mgithubreq Could you try this build on your Trinket M0?
https://adafruit-circuit-python.s3.amazonaws.com/bin/trinket_m0/en_US/adafruit-circuitpython-trinket_m0-en_US-20190328-c6e3b17.uf2

It fixes a USB HID problem that may also affect connectivity. PR for fix is #1721.

@dhalbert Thank you! Unfortunately, I can't test this right now. We have only one Trinket and I already passed it on to the team doing further integration into our target device...

I tried this on an Amazon Fire, and it no longer seems to crash. Unfortunately, the HID keyboard presented by the Trinket prevents the on-screen keyboard from appearing, and there was no obvious way to allow the on-screen keyboard to appear. So I couldn't test it completely. I'm going to close this for now, because it sounds similar to the other scenarios for #1721.