Sometimes when switching from normal mode to Ultra Power Saving Mode, my phone gets stuck. There's no option to switch back to normal mode in the top toolbar and settings. If the recent apps button and home button, a "System UI has stopped working" dialogue pops up, and if the phone restarted, it will get stuck on the carrier logo. The only way out is to perform a factory reset. Is there a way to prevent getting stuck switching between normal mode and Ultra Power Saving Mode, or is there a way to return to normal mode if it gets stuck?