The newest bitmain firmware disables ssh on boot, therefore you can not ssh into machines. Its not a big deal if you have a few machines, but there are many farms out there with hundreds or thousands of miners that automate configuration and reboots using software, this new firmware removes the ability.

They quote "security", but its bologna. Why not give the end user a choice to turn ssh on or off through portal. Any end user with a couple machines can turn ssh off, and farms that tunnel through firewalls can leave it on, our choice.  They are purposely making larger mining operations lives harder to get an upper hand.