My phone couldn't get booted into any modes to recover after I semi bricked it. Now I'm gonna send it back to the manufacturer for a replacement. I master reset it but I don't think I can unroot it that way and there's nothing on the screen when I turn on my phone so I can't turn on things like USB Debugging or Recovery Mode. How can I unroot? Running Android 2.3.4. I'm already past trying to unbrick it.