It does work. During initial setup, when you get to the internet connection step, there's an option to change from wireless to the wired connection. The update took around an hour for me.
In case anyone was wondering the $10 code does work on preorders that have the $10/1600 points offer. I used my code when preordering the Nike Kinect game.
Also I ordered the 1600 points but didn't get the code yet like most others here. The receipt does show up in the last page of my order...
This page should have links to all of the titles that have preorder bonuses:
http://www.microsoftstore.com/store/msstore/list/parentCategoryID.50606600/categoryID.59682300
For anyone who got the $10 email, try buying something. I just tried and I actually got $20 credit. I checked last night and didn't have any credit, so the $20 is only from buying Bulletstorm.
Which game did you buy? I got shipping notice for Bulletstorm on 360 and it only had the $20 credit text. I preordered when the offer was for $10 credit.
For anyone worried about offers changing after you preorder, Amazon has stated you will always get the latest offer:
http://twitter.com/amazongames/statuses/38764905200881664
Amazon just addressed this on Twitter. Everyone who preordered previously will get the $20 credit:
http://twitter.com/amazongames/statuses/38399936064258048
Why do people think the Bulletstorm offer won't apply to previous preorders? Has that happened before on Amazon? Usually they are pretty good about that kind of stuff.