The HTC HD2 has long proved its ability to run Windows Phone 7 — among others like Android — which still makes it an iconic phone to come out from the Taiwanese phone maker's factory. It now gets the ultimate treat, an unofficial Windows Phone ROM which allows for official updates.
The ROM is Build 7.0.7004.0, so it's the original Windows Phone launched last year and is available in English, German, French, Italian, and Spanish, with the possibility of updating all the way to 7720, which is Mango RTM. It's not the ROM though that is a breakthrough but its ability to be officially updated by Microsoft via the Zune software, just like any other legacy Windows Phone. The ROM also seems to retain its jailbreak state after updates, which is great for those looking for registry editing or sideloading of apps.
If you want to run Windows Phone 7 on your HTC HD2, head over to the source link and carefully read the instructions as well as the risks plus feedback in order to make it work.
Source: XDA Developers