Deactivated or inop, tech log or not?

[Superpilot]

An onboard system has been deactivated by maintenance because of a problem getting it to work. Or more accurately they can't be bothered to investigate the issue, so they simply deactivate the system. Such a deactivated/inop entry is not to be found in the tech log. The argument by maintenance is that the system hasn't been commissioned since they sourced the aircraft, so it shouldn't be in the tech log??? But to avoid us mere mortals assuming the system works, they have to put an inop sticker on the controls associated with the system. I'm talking about CPDLC. So, is it inop or is it deactivated? And where would the correct place be to track the fact this system doesn't work because the flight plan sure thinks it does!

[LME (GOD)]

This depends on the company procedures but as a rule of thumb, deactivation requires a minor modification/change authority that would have to permitted by the engineering group. An inoperative component can only be deferred by MEL.
If the aircraft was fitted with CPDLC but is inoperative, ask to see the minor mod paperwork for the deactivation, if it was carried out as part of a larger bill-of-work (check) there may not be an obvious entry in the tech log.

[spannersatcx]

We have a NTC, Notice to crew, in the front of the tech log for such things.