I'm running rsync (installed from Entware) between an AC86U (local) and AX56U (remote) to move some files between the two routers - both at 384.17.
The command:
rsync -avh --inplace --exclude '*.swp' -e 'ssh -p XXXXX -i /jffs/dropbear/private_key'
[email protected]:/[remote_source]...