The ability to brick phones without the consent of the one who possesses the phone inherently indicates that the user does not actually control their phone.
Any information a company possesses on your behalf, including any codes, messages, or instrumentality necessary to brick a brickable phone, must be disclosed if the government agent has a warrant. Your consent is absolutely not required by any known legal principle.
That's just bog-standard liberal-democratic law, consistent with the constitutional order of any modern western country, no need for secret spy agencies or black sites. You don't have allodial title to your cellphone.