Figured I'd post this here too:
I just came up with one for always reading the touch screen joystick as if the origin is the center of the screen (useful for emulators that have a joystick to touch function, as this prevents the joystick from dragging the origin around).
0202C528 = e3a02080 (Mov r2,#0x80) This sets the X value
0202C53C = e3a01060 (Mov r1,#0x60) This sets the Y value
0202b444 = e3a02080 (Mov r2,#0x80) This sets the X value
0202b458 = e3a01060 (Mov r1,#0x60) This sets the Y value
The graphics of the joystick will still move and drag, but the input should always register as the origin being dead center of the screen.
I made this before realizing that Skeletons made a patch, but this should be handy for android users with tincore mapper