Really useful 
I wanted to recover to my local disk rather than the SD card so:
ssh root@10.42.66.66 dd if=/dev/sda79 bs=4M | pv -rab > sfos_backup_sda79.img
Worked for me and got 35MiB/s
Note that you need to set the root passwd in a plain shell before starting sshd as that’s not actually set to ‘recovery’