I was going to try custom Roms but i don't understand how this bootstrapping works. So I bootstrap recovery and install Rom Manger and CWR but from there is there anything special i need to do before i flash a custom rom? After i did those steps i got a lot of force closes on miui, tried to flash CM9 over miui and that messed it up it ,seams some stuff from miui was left over even thoou i did wipe data/factory reset. Do i need to bootstrap every time i flash another Rom or idk?