Skull One said:Yes, it does. iOS operates differently after you have jailbroken it. Think about it this way. Does the jailbreak allow you to do ANYTHING beyond the original intention of Apple? If you answer yes, then the software HAS TO BE altered to allow that to happen.
Not exactly.
Jailbreaking does nothing but make a couple extra directories and install Cydia.
Mobile Substrate modifies the OS. Which is not installed until ou decide to install it, or something that depends on it....which is almost everything.