I know calling a temp-root perma-root or permanent doesn't make all that much sense but if you read on you'll understand what I'm talking about. Recently the guys from TeamWin were able to temp-root the HTC EVO 3D and Sensation but users randomly are losing that root, and it is gone after a reboot as well.
We are all still waiting patiently for HTC to send out an update to devices and unlock their bootloaders so rooting and custom roms can go back to being a much easier task. For now little tricks like this one will have to due. A dev named Eugene373 figured this one out and here's what he had to say.
Everyone knows that currently with any temp root, you still lose links to the SU Binary & Busybox links, it’s just a matter of time before it happens!!
So after digging around somewhat I found an over sight that HTC might use later for system updates via /vendor/bin, who knows at this point though… Anyways, after amount of time the SU Binary along with busybox links if be in system/bin or /system/xbin gets deleted / removed..
Now, what I did was enable the $Path to /vendor/bin which is in the Sensation export PATH..
Any Calls made from this point either be SU or Busybox don’t get deleted nor touched from any App requesting the SU Binary!! I’ve tested this with alot of apps & the Root sticks in place..
Other than Reboot, it might as well be a Perma-Temp-Root!!
This is not a true and complete perma-root method but it will make things easier for the time being. Users not having to redo the temp-root method over and over will be much appreciated until we find a better cure. Hopefully those HTC updates aren't far off, I'm still hoping for a update sometime in July but we will see. Hit the source link below for more info and the install files for this perma-temp-root method.