HI friends,
Since Evo Design has less publicity on forums, so there are very less information available about rooting and other technical issues. I have successfully rooted my Evo Design 4g after upgrading to Icecream Sandwich. Here are the steps
1. Unlock your Bootloader using htcdev (website).
2. DOWNLOAD recovery and put it to the root sd card, Here is the link for CWM recovery for Evo Design 4G.
http://dl.dropbox.com/u/24065431/kingdom%20stuff/New%20folder/PH44IMG.zip
3. Download the root file and put it to the root of sd card:
Root_SuperSU.0.93_Busybox_1.20.2_Update2.zip(file uploaded below)
Copy the PH44IMG.zip(Recovery file) file you downloaded, to sd card
Boot into stock recovery (volume up+home+power), and select "apply update from external storage".
Now select the recovery-PH44IMG.zip file you copied in previous step (this step gives a temporary flash that will disappear after reboot)
After flashing, remove recovery file(PH44IMG.zip) from root of sd card. If not done, phone will prompt for reflash it after every reboot.
After reboot into bootloader mode,You get CWM touch recovery interface
Inside CWM, select "install zip from sdcard". Now, select "choose zip from sdcard" or "choose zip from internal sdcard" (directs to external sd) and point it to the attached "CWM_Root_XXX.zip"
It will add SuperSU, last superuser binary (su) to system/xbin and busybox last version to system/xbin, all with correct file permissions.
Reboot and you get permanent root + busybox installed on your stock kernel.
Note: One can google for detail steps "How to install CWM recovery" and "How to unlock bootloader" for ur phone before performing above steps. This method has successfully rooted my htc design 4G. Try at your own risk. I am not responsible for any damage to your phone
CWM_Root_SuperSU.0.93_Busybox_1.20.2_Update2.zip