I’ve managed to gain ssh access with root privileges to the gateway. To do this I first logged in to the web interface on 192.168.55.1. Log in with user admin and password admin. Then go to system > backup and restore to download a backup to your pc. Ubuntu saves this in ~/Downloads. The backup file is simply a .tar.gz of the gateways /etc folder. Open the file /etc/shadow and copy the hash for the admin password (shown in bold) to all the other passwords. Save the changes and upload through the web interface.
root:$1$kISzvUen$KWbOWvwQwqDkLh0N4cX00/:16755:0:99999:7:::
daemon::0:0:99999:7:::
ftp::0:0:99999:7:::
network::0:0:99999:7:::
nobody::0:0:99999:7:::
admin:$1$kISzvUen$KWbOWvwQwqDkLh0N4cX00/:16755:0:99999:7:::
su:$1$kISzvUen$KWbOWvwQwqDkLh0N4cX00/:17441:0:99999:7:::
giot-admin:$1$kISzvUen$KWbOWvwQwqDkLh0N4cX00/:17441:0:99999:7:::
giot-user:$1$kISzvUen$KWbOWvwQwqDkLh0N4cX00/:17442:0:99999:7:::
The gateway will reboot with all passwords set to admin. Reconnect to the gateways wifi, open a terminal and run the command;
ssh giot-admin@192.168.55.1
enter password admin and you now have full root access to the gateway.
Next step, figure out how to configure the gateway for TTN. If anyone has one of these actually working on TTN can you share your backup file or compare your backup file to the one I posted a link to previously so that we can get an idea on how to set this up for TTN?