unable to connect google coral using OTG port - google-coral

Question

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.

Answer 1

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:
Open the file in your favourite text editor
vim $HOME/.local/lib/python3.6/site-packages/mdt/sshclient.py +86
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

Answer 2

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.
Through serial console to devboard, delete the contents of the /home/mendel/.ssh/authorized_keys
reset the mdt service in google coral devboard using mdt-keymaster
sudo service mdt-keymaster restart
Delete the mdt key in your host computer through rm ~/.config/mdt/keys/mdt.key
Correct the IP issue in NonLocalDeviceError as above
Then try mdt shell
if nothing working, reflash the coral board by using below procedure
Connect your dev board via serial cable and login [Ist terminal].
Once login hit sudo reboot-bootloader to put devboard in fastboot mode.
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
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.