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When I'm running google coral using serial port I'm able to run demo apps but when I'm trying to run google coral using data port (type c cable) I'm unable to connect with a dev board

rahul@ubuntu:~$ mdt shell Waiting for a device... Connecting to wishful-yarn at 192.168.101.2 Key not present on wishful-yarn -- pushing

It looks like you're trying to connect to a device that isn't connected to your workstation via USB and doesn't have the SSH key this MDT generated. To connect with MDT shell you will need to first connect to your device ONLY via USB.

Rahul Tripathi
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  • Solution - https://github.com/f0cal/google-coral/issues/58 – Rahul Tripathi Nov 20 '19 at 11:25
  • The solution proposed by @Rahul Tripathi in [github.com/f0cal/google-coral/issues/58](https://github.com/f0cal/google-coral/issues/58) downgrades Mendel Linux from 'day' to 'chef'. The new release was improved heavily and has several new features, so this might not be convenient for users who want to stick with the new release. – Andreas Gschossmann Nov 25 '19 at 16:09

2 Answers2

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The problem is caused by the PyPI package mendel-development-tool itself. This error is raised by the 'NonLocalDeviceError' exception as can be seen in line 83 of command.py in the code of the package. Whenever the IP of the device does not start with 192.168.100, this exception is raised by sshclient.py (in line 86). This worked for the last Release of Mendel Linux (chef), since the IP address of the usbnet connection was 192.168.100.2. In my case the new Release of Mendel (day), which came lately in November 2019 had the IP 192.168.101.2. To check the IP check the output of

mdt devices

If you installed the package using pip3 as user, like it is recommended by the documentation (pip3 install --user mendel-development-tool), this can be fixed by a quick local patch:

  1. Open the file in your favourite text editor

    vim $HOME/.local/lib/python3.6/site-packages/mdt/sshclient.py +86

  2. Replace line 86, which is 

        if not self.address.startswith('192.168.100'):
        raise NonLocalDeviceError()

    by the following code

        if not self.address.startswith('192.168.10'):
        raise NonLocalDeviceError()

Most likely the authors might update the PyPI package to this solution, since the master branch of command.py already has the proposed code. Once the package has been updated you just have to update it on your host.

pip3 install --upgrade mendel-development-tool
Andreas Gschossmann
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  • Andreas thank you for correcting me after changing suggested changes i'm able to connect via usb(type-c) but as written in doc new os have support of cv2 but no module cv2 import error i'm getting – Rahul Tripathi Nov 27 '19 at 08:47
  • This doesn't work on macOS Catalina. Any ideas how to fix this? – evolved Feb 17 '20 at 21:47
  • Yep, same problem here. This was because the EdgeTPU generates 2 USB interfaces: usb0 for ECM, and usb1 for RNDIS. Only the 2nd properly connected and got populated with 192.168.101, as .100 was already reserved. Luckily, once the keys are properly populated, that's not a problem anymore. – Adrien Leravat Mar 15 '20 at 05:27
  • Same problem here. Thanks for your answer!! – Coco Yen Mar 17 '20 at 07:57
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The issue is google coral dev is connecting to WIFI also.

First you need to delete the wifi in google coral using nmtui --> edit connection --> delete.

Then connect your host computer to google coral dev board through USB C OTG data cable.

  1. Through serial console to devboard, delete the contents of the /home/mendel/.ssh/authorized_keys

  2. reset the mdt service in google coral devboard using mdt-keymaster sudo service mdt-keymaster restart

  3. Delete the mdt key in your host computer through rm ~/.config/mdt/keys/mdt.key

  4. Correct the IP issue in NonLocalDeviceError as above

  5. Then try mdt shell

if nothing working, reflash the coral board by using below procedure

  1. Connect your dev board via serial cable and login [Ist terminal].
  2. Once login hit sudo reboot-bootloader to put devboard in fastboot mode.
  3. Open 2nd terminal and perform below steps to flash mendel linux
cd $HOME/Downloads
curl -O https://dl.google.com/coral/mendel/enterprise/mendel-enterprise-chef-13.zip
unzip mendel-enterprise-chef-13
cd mendel-enterprise-chef-13
  1. bash flash.sh

Once Flashing the board complete shutdown google coral sudo shutdown now

Connect devboard again, then follow the previous steps 1-5 again.

Elikill58
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Arivudainambi Kuppudass India
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