Adding a Firmware Lock to 2.6

I want to lock my APM2.6 using a firmware user authentication prompt. Essentially, if someone plugs into the microUSB port, they would need to authenticate, without which, they wont be able to see the parameters. I tried MAVLink 2 signing and locking Mission Planner, but that wont suffice.
Does anyone have any suggestions about adding a firmware lock essentially?

Not with obsolete and unsupported hardware like the APM but there was one discussion:
Block USB Port