How are you getting your phone out of standby if your power button isn't working? I just got myself really confused when I thought of that.... also it sounds like you have the stock recovery and not sprecovery. Your ONLY issue at this point it seems is the power button (obviously) and that you have the SU app on your phone. If you don't have a custom recovery and only have the stock one you will ONLY be able to run update.zip files that are official. Since you are on ESE81 none of the update.zip files that provide root will work. I'm still confused to getting out of standby if the power button doesn't work though.....are you sure it doesn't work?