XDA Senior Member mengfei has posted a tutorial that will help get the HTC HD2 to triple boot. It is not a very stable method and mengfei says that not everyone will be able to accomplish this. The method works by creating three partitions using a SD card and the internal memory. Then users install ROMs to those partitions. It’s a loose description, as the tutorial is actually much longer.
To get started users will have to make the partitions. Here is what users will need:
1 FAT32 Partition
1 EXT4 Partition
1 WP7 Partition
MiniTool Partition Wizard Home Edition (MTPW) using this to do those above.
In the tutorial, users will be installing WP7 first, then the other operating systems afterward. The whole process will take some time. However, once finished, the HD2 will be able to boot into any one of three different ROMs. Users have reported that the method works, albeit with some tweaks here and there to the process.