well, its easy if you understand the system. i mean, you need to understand te strings or HEX or somethign like that. ofcourse you need to know programming and things like that.(basic proramming is okay if you remember it) and ofcourse you need to be resourceful and experience. because if make the wrong procedure like for example no.1 is you deleted some files on iphone, your iphone might not work properly or maybe stop it from working.. but if you destroyed it, dont worry, you can turn your iphone to some use like paper-weigth. ;)