So this error could be specific to this device?
It could be. I suppose you’re using the procedure in the following post to open the ssh shell, right? HowTo: SSH into host device
If you happen to have direct access to the local network whether the device is, it may be possible to ssh directly to the device with the command:
ssh -p 22222 root@<ipaddress>
replacing <ipaddress> with the device’s local IP address such as, say, “192.168.10.10”. (To find the device’s IP local address, commands like arp or balena scan may be helpful.)
If the device is running a development image, no password or ssh key setup is needed. If it is running a production image, an ssh key has to be added to config.json. (I appreciate you may no longer have access to the device to add a key in this way…).