I’ve previously rooted my Desire HD, but reverted it back to stock a little while ago, after HTC announced they were NOT going to release an Android 4.x update for the DHD.

I tried fre3vo repeatedly, but since I was using a newer Sense-version, I had to use a different method, which is described here.

After that, gaining permroot using Visionary, installing ClockWorkMod and flashing a custom ROM were a piece of cake.