Hi there! (again) I solved the "mouse-jumping-problem" by first initializing a standard VGA 640x480 mode (to make the mousedriver recognize graphics mode) then the mouse and finally zRes"SomeMode". I have attached the code-fragment doing the "trick". Regards Tim H. Petersen inregs.h.ah = 0x00; /* <- goto graphics mode */ inregs.h.al = 16; int386(0x10,&inregs,&outregs); memset(&r,0,sizeof(union REGPACK)); r.w.ax = 7; r.w.cx = mouse->min_range_x; r.w.dx = mouse->max_range_x; intr(0x33,&r); r.w.ax = 8; r.w.cx = mouse->min_range_y; r.w.dx = mouse->max_range_y; intr(0x33,&r); inregs.w.ax = 0x000F; /* <- set Mikeys/pixel-ratio */ inregs.w.cx = mouse->mickey_x; inregs.w.dx = mouse->mickey_y; int386(0x33,&inregs,&outregs); inregs.w.ax = 0x001A; /* <- set mouse sensitivity */ inregs.w.bx = mouse->sensitivity_x; inregs.w.cx = mouse->sensitivity_y; inregs.w.dx = 0x0; int386(0x33,&inregs,&outregs); setgraphmode(_800x600x8);