Im now working on a Node MCU based project but the problem is that i cannot upload the code to the board. Further more whenever i connect the usb to the NodeMCU my keyboard stops working and only works again after i turn off and on my pc this happens whenever i disconnect and connect the Node MCU. The error is COM port is not found or board is not connected and sometimes after i disconnect the Node MCU my system gives a message The Last USB device malfunctioned Can anyone help I'm using a basic NodeMCU 12E CP2021??

1 Answer 1


I'd check 3 things:

  1. If it's a specific USB port/cable problem, not related to the NodeMCU itself (your said it interacted with your USB keyboard, what makes sense if it's a computer-usb issue). Try to connect the NodeMCU to a different USB port/hub in your computer using another USB cable.

  2. Of course it could be a USB-Serial driver issue. Please make sure what chip is used on your NodeMCU (CH340 or CP1202) and make sure the correct driver is installed.

  3. Most important - you must make sure your Serial pins on the NodeMCU (TX, RX) are not connected to anything during program upload. They are bridged to the Serial connection that is coming from the computer (through the USB-to-Serial chip) and interact and interfere with them.

Good luck!

  • 1
    Thank you apparently its y breadboard which had a problem as it made a connextion between the rx and tx Jan 21, 2021 at 8:00

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