HTC HD2 owners have many choices: they can stick with Windows Mobile, run Windows Phone 7 or switch to different flavors of Android. Some might also want to be able to dual boot Windows Phone 7 and Android, darrengladysz @ XDA detailed the steps to run Windows Phone 7 from the HD2 NAND memory and Android from the SD card of the HTC HD2.
Note that you cannot run both Android and Windows Phone 7 from the HD2 NAND memory so you will need to have Windows Phone 7 in the NAND memory and an SD Card with Android.
You can get all the instructions on how to dual boot Android and Windows Phone 7 @ [REF] Tutorial: How to partition sd card to run wp7 and android from same sd card
Geolo @ XDA created a YouTube video based on those instructions:
Don't forget to follow us on Twitter and join our Facebook Fan page to stay updated.