...so if I may give you a suggestion, let IT personnel do their job and implement an easier way to set and protect a static IP in the firmware. Nothing wrong with the SSH and connman for me, but somebody with less linux experience could be in trouble and normally people dealing with design are not linux experts (nobody is questioning why you use connman instead of /etc/network/interfaces so please do not question why we prefer to have printers on static IPs outside the DHCP area).
Here the full guide for anybody who might need it:
1. on the printer panel enable developer mode (printer restart needed)
2. SSH to the printer (default credentials would be root/ultimaker)
3.
$ connmanctl services
and note the name of the interface that must be configured (remember: the machine has 2 network interfaces): from now on that will be the <service> (no "<" or ">" needed, just the service/interface name which will look like ethernet_<MAC_ADDR>_cable for the wired one, the other one I didn't have time to check )
4.
$ connmanctl config <service> --ipv4 manual <IP address> <netmask> <gateway>
at this point the SSH connection will be broken because the printer switches immediately to the new IP so verify if everything went fine and
5. on the printer panel disable developer mode
just in case you want to re-enable DHCP the command is:
$ connmanctl config <service> --ipv4 dhcp