This morning it was so quick to boot up I couldn't really time it. But.
I drove the car out of the garage and wanted to use autohold to keep the car there while I got out and closed the garage door. No autohold. Not only did the car continue to creep after I'd given the brake pedal that extra press, but I couldn't see the autohold icon on the screen at all. I had to engage the parking brake manually, although I used the lever on the right, not the P function on the dial.
I had made the mistake of cancelling the LKA when I first started the car in the garage, thinking that would do it. Not a bit of it. As soon as I got back into the car and pressed the brake, bloody LKA came back on, so I had to cancel it all over again.
So even though the car booted up really quickly, it wasn't a terribly quick start. It doesn't seem to have an easy way to let you pop out of the car for a minute or two without everything going back to square one. Where the hell the autohold function was when I needed it I have no idea at all. It was certainly there and functioning later in the drive because I used it a couple of times.