You could search it here :
http://forum.xda-developers.com/forumdisplay.php?f=812
otherwise, you'll consider some things:
- You MUST read all the guides carefully. Once you are feeling dizzy, take a break
- You WILL LOSE anything stored on your phone (Since you didn't backed your phone up, and you want to downgrade it, it means that you need to re-"format" your phone)
- You MUST read carefully all of those texts on that guide, otherwise I'm afraid you'll download an invalid version and it might (I don't know whether this is true or not) damage your phone
*Sorry, I couldn't find the roms for hTC Trophy.. Please search there.. I'm having an headache now. previously, I posted the link to download ROMs for hTC Mozart devices.