My S2 updated to 4.1.2 today. All seems workinmg except my lock screen. I have Go Launcher installed and before update had my own wallpaper on the lock screen; I now have Samsung London Olympic wallpaper there, instead of the much more useful wallpaper I used to have. Not worried about the wallpaper on the Home screens just the lock screen. Can any one please give me instructions on how to change the lock screen wallpaper?