The Dropbear mini ssh daemon doesn’t recognize $HOME/.ssh/authorized_keys files. However, you can configure authorized public keys in /etc/dropbear/authorized_keys (using the same format).
For example, you can do:
scp .ssh/id_rsa.pub root@fon01:/etc/dropbear/authorized_keys
The next time you access your Fonera box, you won’t need to enter root’s password 
.
