Ok well there are two threads giving excellent guides on how to permaroot your phone, however PaulOBrien recently updated VISIONary to give a two-click permaroot to the desire HD and so we can get an easy basic permaroot without messing around with adb, terminal and whatnot!
Obviously this just achieves root, but doesn't get S-OFF. It also doesn't rewrite your Hboot...
The noob guide (for people like me...)
Step 0.5: If you have already got temproot using VISIONary r11 or earlier, make sure you uncheck 'temproot on startup' and then reboot your phone. Then once your phone has rebooted, remove VISIONary, reboot, and proceed with the steps below! (To let you know why, if you have temprooted with previous versions of VISIONary, r12 conflicts with it - this is because r12 checks for root and thinks the device is already rooted if a previous version has temprooted it...)
UPDATE: If you are having problems with your device saying it is already rooted try VISIONary r13 which Paul released as a fix I believe:
http://content.modaco.net/dropzone/c...ryplus.r13.apk Original post on MoDaCo - http://android.modaco.com/content-pa...root/page/120/
After you are all prepared:
Step 1: Download VISIONary r14: http://android.modaco.com/content/ht...ne-click-root/ and install it on your DHD
Step 2: Temproot your phone using VISIONary
Step 3: Use the Permaroot option to Permaroot your phone!
This is just a guide to get basic Permaroot on your DHD. However, if you would like to get S-OFF then please go to the guide written by sfjuocekr. He has prepared and written an excellent and (relatively) easy way to get it.
FOLLOW HIS INSTRUCTIONS EXACTLY TO AVOID YOUR DHD BECOMING A GORGEOUS ALBEIT USELESS BRICK
Here it is: http://forum.xda-developers.com/showthread.php?t=835746
As a final note, I'm not sure whether this (VISIONary) works on all kernel versions, but give it a try anyway! There is also an option in the app to get a one-click unroot.
ALL credit goes to PaulOBrien for making and updating this fantastic app!