Static ip on remote unit eth0

I’m having no problem connecting remote unit to a LAN that provide DHCP via a usb->eth bridge
my point is when I try to connect it to a dumb device that requiring that ip on the remote should be set statically as no su is aviable on remote I dont know how to do is there any solution to do that ? may be configuring it via OEM firmware special tweaks ?
thank’s for any idéa
@Michael_Oborne as you are so efficient in finding solution for my strange networks questions may be you have a small idea ??? :wink:

anything that requires a custom remote unit we direct to our oem program. if you can make it work within the existing ip range, then its a no issue, but there are costs associated with custom setups like your are trying to archive.