Is it possible to roll back to 4.1.1 without rooting as I am beginning to detest this phone since it's last update. It constantly lags, screen rotate stops working, internet doesnt work very well especially on wifi and I am constantly rebooting the phone. Final straw was last night when it just shut off and appeared dead apart from holding the power button showed a battery icon on screen, it finally came back to life after pulling the battery.