It looks like Microsoft have taken a leaf out of Google and Apple's linking of user accounts to individual devices, with a freshly leaked Windows Phone 7 architecture guide confirming that owners of smartphones running the upcoming platform will be required to register a Windows Live ID on first boot. Tweakers acquired a confidential internal document which confirms that not only will new owners have to sign up for Microsoft's ID system if they want to use contacts sync, any of Microsoft's other services, or even download apps from the Windows Phone 7 Marketplace, the company have also taken steps to prevent the OS being run on unofficial hardware.
According to the document, devices will come with a Genuine Windows Phone certificate; without that, the owner's Live ID won't be accepted and they potentially will be unable to get past the EULA. It's likely something which will be hacked around by the ROM merchants over at xda-developers, but it's a sign that Microsoft aren't entirely pleased with the prospect of devices like the HTC HD2 being unofficially upgraded to the newer platform.
Other details include confirmation that Microsoft will be taking responsibility for OTA and tethered firmware updates for future iterations of Windows Phone 7, together with news that - as it stands - there's no support for Bluetooth 3.0. However OEMs will be responsible for Direct3D drivers, potentially leading to situations where certain handsets fall short of the graphics performance the basic hardware is capable of.
Interestingly, carrier and OEM customization will be heavily limited, with a maximum of six apps taking up no more than 60MB permitted; they'll also be able to add their own live tiles on the homescreen, change the operator logo and switch the default search engine within Internet Explorer (though Bing will remain default everywhere else in the smartphone).