I don't think this matters much when you are modifying the firmware.
Apple says it isn't as simple as you claim. Wake up. Don't listen to that nobody on "Trail of Bits," he doesn't know what he is talking about. That's what everyone has been telling you. Apple has now answered and they say it would take a team of between six and ten engineers, two to four weeks before they can even start testing on OTHER iPhones to make sure nothing else breaks. Plus they'd need a project lead, a document writer, and THEN a team to write the interface for the remote connection to run the brute force passcode input from a system never designed for that purpose, depending on how they intend to do that. PLUS they have to document every step of how it was done for when they are hauled into court by any potential defense attorney challenging the evidence.
YOU just assumed they would be changing the firmware.