Please point me to the iPhone application launch time guidelines.
I see that there is a hard limit of ~24 seconds. OS kills application if it did not started in that time with the message:
com.bundle.id failed to launch in time
There is also a QA article on this. (24 seconds is the time until OS on my phone kills the app.)
But I think that there should be a shorter soft limit somewhere in the docs. However, I was not able to find it.
From the iPhone Application Programming Guide
I don't think you will find any numeric limits in the documentation. Apple has been vague about that stuff for a reason. They don't want to come out and say that "apps that have a launch time greater than x seconds are not allowed". Your app may only get rejected from the App store if it's launch time was so long that it was simply unacceptable/unusable. I'm not sure where the 24 seconds number came from, but perhaps that is what Apple uses in it's automated testing for App store approval.
Apple's stance is simply: "Your app's launch time should be as short as possible. If your app takes a long time to launch, users will be less inclined to use it, which will only hinder your app's success." Seems pretty reasonable to me.