The one (1) percent battery mod for the HTC One shows battery symbol in 1 percent steps in your status bar. The 1 percent increment or decrement are also shown during charging. Do this MOD at your own risk. We are not responsible for anything.
How to install this mod – Flash zip (get it from here) in Recovery or via ROM Manager. So, yes, you need to have an unlocked HTC One and you should have rooted it with CWM recovery installed.
It is just sad that HTC phones do not show battery in 1%. So, you either have to install a custom ROM or do this mod. If you feel like disabling this MOD, just flash the original one from here using the same steps mentioned few lines before.