You guys know that you can make a system dump WITHOUT root?
Download Rhythm Software's file manager on Google Play.
Now open it and go up until you can see system.
Copying that is possible. Copy it to /sdcard and you got yourself a dump.
That's what I figured would happen! It looks like this may be an option to root the 4.1.2 build. It worked on the One S and the Nexus 7, which gives me hope.
RUU stands for ROM Update Utility and is a Windows executable file that can flash and restore a HTC device. There are ways to extract binaries from this file, and if there are no root exploits that will work on this phone, we will need to extract the original recovery.img from that RUU to build a custom recovery, in which at that point allows us to flash SuperUser.apk to get root.