@Dared, did you check that you have an IP address for the computer end?
There's no DHCPD in Jolla when you enter recovery mode, if you have the correct drivers a new IP interface will appear but you need to give it an address in the same subnet as the device is, before you can connect to it.

If that's not done correctly, and you try to telnet to the device, your telnet packets will just go out your default route