Without knowing how this device is used or its connectivity, a risk based analysis might solve your problems. We used PCs in production. To solve cybersecurity we removed the network and wireless ports, USB Drives, serial connectors and CD Or blue ray players and other floppy drives. It was essentially a one dog pony with no access to external factors other than a keyboard. If we needed to update it, IT would remove it and engineering would install new software.
If your device requires a connection though this approach wont work.