I have an embedded system which is un-writable (must be flashed).  I am trying to manually install sshd.  I try to start
 sshd giving it path to key and the config file.  But I get 

Privilege separation user sshd does not exist

I created a sshd user with this;

passwd:
sshd:x:74:481:Privilege-separated SSH::

group:
sshd:x:481

shadow:
sshd:!!:14769::::::

But I still get this message.

Thank you,

Durwin