Ok, what are you talking about? Don't just post random questions without searching the forum... a backup loader is a homebrew that lets you boot backups (obviously), and the best are either softchip or .3 Gamma. I have no idea what you mean by boot loaders, maybe you mean preloader, but if you don't know the difference between the two you don't want to be messing with this. I'm not trying to be a jerk, but there are so many different guides and topics on how to do things like this it's ridiculous not to have searched for them...