Teensy uploader hangs (4.1)

[tomicdesu]

I'm using Arduino 1.8.x on a laptop with A311D CPU, 8GM ram, Debian unstable, and Teensy 4.1. "Most of the time" the uploader works correctly -- erase, program, then returns to the "press Button on teensy..." ready state. But often enough it hangs part way through PROGRAMMING..., times out, say DOWNLOAD ERROR in red, then...

Recovery is sometimes simple -- press the button on Teensy, but other times Arduino IDE loses the port, then things get difficult, I haven't found a simple path back, I end up powering off teensy, quitting the IDE, etc.

Usually the uploader turns off Automatic mode (Operation --> Automatic mode).

Once it fails, it seems to then fail many times. Or I can go days without a failure.

I can't discern anything I'm doing differently. The CPU on this machine is very slow, I don't think this has ever happened on a fast i7 4GHz machine with 64 GB RAM.

Any suggestions on avoiding this error?

 

[PaulStoffregen]

Usually download errors are due to poor quality USB cables or other physical connectivity or power problems. Before you pour a lot of time into the software side, check the most common things.

On the software side, the 2 places you might discover useful info are the Teensy Loader verbose info log, and the Linux kernel messages. In Teensy Loader, click Help > Verbose Information. That window has a Log menu that lets you save it all to a file, which might help if you want to share it here. To see the kernel log messages, try "sudo tail -f /var/log/syslog" or "sudo dmesg --follow". How exactly these are accessed varies with different Linux distros, so if neither of these commands work try searching for help specific to your Linux distro.

If you have a voltmeter, you might connect it to VIN & GND on Teensy to watch the USB power. Or better an oscilloscope which can show you very rapid fluctuations that a slowly updating multimeter would miss. But this is a long shot, so I wouldn't pour a lot of time into it. Or you could place a powered USB hub between your PC and Teensy. Just make sure the hub has its own power cord so it really is powering Teensy rather than depending on your PC's power.

Whether any of this will really help, I don't know. But if you want to investigate, these are the best ways to try troubleshooting and to (maybe) collect more info.