Flashed my HTC Desire HD today. Since it is/was branded I had to make a GoldCard first. After that I was able to work magic :)

I used the info on the following links, in succession:

http://www.addictivetips.com/mobile/how-to-make-gold-card-for-htc-desire-hd/

http://forum.xda-developers.com/showthread.php?t=905003

http://www.addictivetips.com/mobile/how-to-permanently-root-htc-desire-hd-complete-guide/

http://www.addictivetips.com/mobile/how-to-gain-s-off-radio-and-engineering-on-htc-desire-hd/

http://forum.xda-developers.com/showthread.php?t=840040

:-)

Oh, this one came in handy as well!! - https://www.dropbox.com/s/b7cvmjy71pagq39/ROMs