Solution:
Every IPHONE 7 needs over a minute to boot when you have your headphones plugged in while you boot the Device. (only if you have plugged in the headphones, normally it takes about 17-20 sec. to boot up)
Apple still didn't fix that, it happens on all iOS versions from 10 to 10.2 and on 10.3 Beta too. On all IPhone 7 ( I've tested it)
And "HEY Siri"doesn't work too while the device is in the pocket with the headphones plugged in. (exactly where you would need "hey Siri" the most)
This bothers me for weeks.
Apple removed the headphone jack and there are all sorts of failures when you plug in your headphones over the lightning port. Sometimes it doesn't recognize your voice over the microphone and you have to plug it out and in again. And it's crazy because those lightning headphones from the iPhone 7 work properly without failures on the iPhone 6. But the iPhone 6 doesn't need over a minute to boot with headphones plugged in.
Many people don't use headphones or "Hey Siri" all the time, they don't recognize it at all.
It's most likely a software bug and I hope Apple will fix it very fast along with the other issues depending the lightning headphones.
It's not nice to call people "crazy"(tinfoil, exaggerating) etc. if they have an issue with their device only because you can't reproduce it.