Trouble uploading to a-star32u4/Leonardo


We’re having hit-and-miss success with uploading code to Pololu’s A-star 32u4 (similar to the leonardo) using pio. We have a number of boards and computers, and the problems follow the computers. That is, my computer can program every board and someone else’s can’t program any.

The failing computers, however, can upload with Arduino and they can also connect to a Serial stream from the boards (after they’re programmed with Arduino).

The issue appears to be tied to the COM ports (these are all with Windows). There are lots of connecting/disconnecting chimes, and we can see ports “coming and going” in the Device Manager. We’ve tried the “double-tap” method at various times to put it into boot mode, but that rarely helps.

Has anyone seen this before? Any idea what to try to solve it? Is it a timing issue? Can anyone suggest something to try/test?

Here’s some output from the upload:

Looking for upload port...
Auto-detected: COM7
Forcing reset using 1200bps open/close on port COM7
Waiting for the new upload port...
Uploading .pio\build\a-star32U4\firmware.hex
Connecting to programmer: .avrdude: butterfly_recv(): programmer is not responding