My friend tried to jailbreak his iPhone 3gs with blackra1n but he doesn't know what hes doing and he doesnt even know what version he has so i don't know if maybe he tried on like 3.1.3 or something. But now it won't turn on. It shows the apple logo for a minute and then it turns off. I want to be able to get it to turn back but I can't find a solution. Any help?