Most don't, but they're usually equivalently locked down nevertheless.

UEFI on x86_64 and phones are not comparable when it comes to being "locked down".

	▲	seba_dos1 3 hours ago \| parent [-]
		Are you sure? Note that the comment you replied to does not even mention phones. Locked down Secure Boot on UEFI is not uncommon on mobile platforms, such as x86-64 tablets.