if you use the pycom firmware tool and select "development" in the type dropdown on the communication page instead of "stable" you'll flash the latest release candidate that should have a fix for this.
@robert-hh Sorry, I misunderstood. I didn't take the pin's voltage with the 1V connected, however I took the voltages of other pins without anything connected. I think the input-only pins were fine, as was pin 20 (and a few others) but some GPIO pins were outputting between 1-3 volts.
@Officina I just tried running the device with 3.3 V on Vin, and it works. At the moment, the DC in is at 2.95 V, and still running. According to the data sheet of the regulator, it goes into a bypass mode if the input voltage is too low, and that's what I wanted to confirm.
So it looks as if is more safe to run with a low Voltage on Vin.
Hi...i am a new user here. As per my knowledge 5.6v is out of spec and should be considered unsafe. Most likely it will work, since USB ports tend to be poorly regulated and these devices take that into account with lots of safety margin, but you risk your player doing so. You might want to look into putting together a 5v regulator circuit to be safe.