@mraj By hardware or by software? By Software: if you have a communication defined, you can define a command which leads the Lopy to do execute machine.reset(). By Hardware: You need extra hardware, which depending on what you need either toggle the reset pin or power off/on the device. A separate small micro could do that, maybe even the PIC which now resides on the various expansion/ensor boards. There a subtle (unintended I guess) differences between machine.reset(), pulling the reset pin and power cycling the device.

@tealbrains & @Xykon : thanks all , that was that ! sudo dfu-util -D ./expansion3_0.0.9.dfu -R -v (I had added my user to dialout group already : not enought)

@re The LoPy4 has like any xxPy device a WiFI connection and starts both a FTP and Telnet server. So you can use ftp and suitbale ftp clients like FileZilla and FireFTP to manage files on the LoPy4. see the FTP section of the docs: https://docs.pycom.io/chapter/gettingstarted/programming/FTP.html You can configure both clients to donwload/upload files into the editor of your choice when you double-click them in the devices file pane.

I found out what was the problem: not the cable, not the up to date expansion board3, but simply the out-of-date lopy4 firmware. Updating it fixed it!

@xykon New version 1.10.0.b4 is now available. You can download it directly via this link.

@gnm Glad to hear it finally worked :) I hope the rest of the getting-started experience will be smoother but don't hesitate to let us know if you need anything further.

Hi @xykon thanks for the info and quick response :-) ... I've not really studied udev rules on my Linux mint machines. However adding dialout did not effect the behavior of 'cutecom'. Changing the read write permissions on the USB device survives reboot. I'm sure if I have a different device take USB0 then I will be stuck again. Any info on how files are copied to and from the device or is anyone in the community looking at a plugin for pycharm? Great stuff - keep up the good work... :-) Kind regards, Nicholas.

@robert-hh Thanks. it is working with 115200.

@jacquej1 You should create a new post as your problem is really different from the original I posted to avoid confusing people. That beeing said, I see a typo on address path "/dev/ttyUS0" should be /dev/ttyUSB0" If you want to continue the discussion please create a new topic.