Ok the reason bootmii is booting at startup is because you have an sd card in your wii that has the bootmii folder (with 3 files inside) on it. It will boot up everytime. What I did was take those files off that sd card and place them on a seperate sd card and use that card only for bootmii. On your sd card you would have a bootmii folder which would have 3 files inside it. Those are the files that cause bootmii to start up. You would also have a nand bin file on the sd card if you ran a nand backup. Also if you installed preloader version .30, it will also boot up everytime even if you have autoboot set to wii system menu. That was 1 of the problems with that version. Try installing an older version (which will overwrite your current one) and set autoboot to system menu and it should work.