My app starts and runs on the new iPhone 6 Plus (or iPhone 6) in the simulator, but elements that I know are supposed to be small on the big screen (i.e. hard coded CG
Adding a correctly sized LaunchImage seems to be enough (setting an incorrectly sized image won't).
Also adding the new "Launch Screen File" should work:
You must set correctly sized LaunchImages
For more information about LaunchImages and icons see this documentation
https://developer.apple.com/library/IOs/documentation/UserExperience/Conceptual/MobileHIG/IconMatrix.html
use Asset Catalog Creator from mac app store.
https://itunes.apple.com/gb/app/asset-catalog-creator-app/id809625456?mt=12
give it any image and it will generate all the correct launch images and icons in a xassets file.
This should stop the scaling of the whole app on iphone 6+
It looks like setting a launch screen file in the "App Icons and Launch Images" section of your project settings, or adding iOS 8 images to your launch image catalog, will enable "native" resolution.