I have my problem still unsolved Splash screen is landscape although the whole game is in the portrait mode. SpriteBuilder + cocos2d , so I see only one way.
How to remove splash screen at all, so that game loads at once ?
This is not possible. An image named Default.png (or under a similar name, depending on the device and what the app supplied) is always loaded when an app launches.
This is done by iOS specifically because no app can technically launch instantly (as in: within a tenth of a second or two).