MicroPython Forum (Archive)

I have a WeMos D1 Mini V2 board. I'm able to erase the flash and upload firmware to it, but when I try to access it via serial, I get no repose. The best thing I can get is some garbage when I hit the reset button. This is my second board. The first board that I got about a month ago (same board from the same seller) worked completely fine.



Here's the ebay item listing:
http://www.ebay.com/itm/D1-Mini-V2-Mini ... 2749.l2649

EDIT:I did try it with multiple computers and got the same result. I also tried it with a daily build and also got the same result. I then decided to use it with the Arduino IDE, and serial worked just fine.

Hi
How do you access the serial? I think you may need to specify the baud speed. In my case, also a d1 mini, it worked with speed 115200 using the command:

microcom -s 115200 /dev/ttyUSB0

Also for me it worked in one USB port while the other couldn't do it.

I did specify the baud speed (screen /dev/ttyUSB0 115200).

@rpi_nerd Given that you've already got one board working I think we can take it that you know what you're doing And given the fact that many of us (including myself) have used the D1 Mini we can take it that the board should work.

So my conclusion is that there's something amiss with your example. My guess is that the Flash chip is either too small or defective. Perhaps the Arduino firmware build is smaller? Given that it works with Arduino you might like to look at this thread which explains how to determine Flash size under Arduino viewtopic.php?f=16&t=1777&hilit=flash+size.

I just checked it under the Arduino IDE and it verified the the flash size is 4MB. Are there any tools available to check if the flash is good/bad?

Given that you can't run MicroPython I think you'll need to look in the Arduino forums. But one thought that comes to mind is to try the verify option of esptool - something along these lines:
This will do a readback check of the firmware. Hardly an exhaustive test, but if it fails it would give an indication as to why it won't run.

I've been using the --verify option, and I've been getting verify OK every time.

Same issue with me. Posted here: https://electronics.stackexchange.com/q ... hon-prompt
Can any body identify the issue?

Thanks

I took a working Wemos D1 Mini and flashed a build produced last week. Initially it produced error messages saying the filesystem was corrupted. So I erased the flash and repeated, this time successfully.

If you guys are getting no REPL after an erase flash/reflash sequence I'm out of ideas. Could it be a problem with knockoff clone hardware?

A couple of weeks ago I faced the same situation with an ESP8266 board. All the hints found in the net haven't been helpful. At the end I just flashed an older firmware version and then it worked fine.