How do I create launch images for iPhone 6 / 6 Plus Landscape Only Apps?

I found a workaround that makes landscape only launch images work on iOS 8 GM. I ended up using the UILaunchImages array in Info.plist. The trick is to get image to show up that doesn't explicitly support landscape (iPhone 4/4S, iPhone 5/5S/5C, iPhone 6) you need to specify duplicate entries. See my example below. This is for a landscape only phone app that supports both orientations for iPad. iOS 7 will fallback to the default image names.

All iPhone launch images need to be rotated into portrait orientation as usual EXCEPT for the iPhone 6 Plus launch image. It natively supports landscape orientation launch images, so you need to leave it's launch image in landscape orientation.

Here are relevant bits of your Info.plist:

<key>UILaunchImages</key>
<array>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default</string>
        <key>UILaunchImageOrientation</key>
        <string>Portrait</string>
        <key>UILaunchImageSize</key>
        <string>{320, 480}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default</string>
        <key>UILaunchImageOrientation</key>
        <string>Landscape</string>
        <key>UILaunchImageSize</key>
        <string>{320, 480}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-568h</string>
        <key>UILaunchImageOrientation</key>
        <string>Portrait</string>
        <key>UILaunchImageSize</key>
        <string>{320, 568}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-568h</string>
        <key>UILaunchImageOrientation</key>
        <string>Landscape</string>
        <key>UILaunchImageSize</key>
        <string>{320, 568}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-667h</string>
        <key>UILaunchImageOrientation</key>
        <string>Portrait</string>
        <key>UILaunchImageSize</key>
        <string>{375, 667}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-667h</string>
        <key>UILaunchImageOrientation</key>
        <string>Landscape</string>
        <key>UILaunchImageSize</key>
        <string>{375, 667}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-736h</string>
        <key>UILaunchImageOrientation</key>
        <string>Portrait</string>
        <key>UILaunchImageSize</key>
        <string>{414, 736}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-736h</string>
        <key>UILaunchImageOrientation</key>
        <string>Landscape</string>
        <key>UILaunchImageSize</key>
        <string>{414, 736}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-Portrait</string>
        <key>UILaunchImageOrientation</key>
        <string>Portrait</string>
        <key>UILaunchImageSize</key>
        <string>{768, 1024}</string>
    </dict>
    <dict>
        <key>UILaunchImageMinimumOSVersion</key>
        <string>8.0</string>
        <key>UILaunchImageName</key>
        <string>Default-Landscape</string>
        <key>UILaunchImageOrientation</key>
        <string>Landscape</string>
        <key>UILaunchImageSize</key>
        <string>{768, 1024}</string>
    </dict>
</array>

The pattern has changed for the iPhone 6 etc

iPhone 6 (750x1334):

Default-375w-667h@2x~iphone.png

iPhone 6 Plus: (1242x2208)

Default-414w-736h@3x~iphone.png

[email protected] (For Landscape)

Note if you support iPad then you must rename your iPad Default images to append ~ipad e.g. Default-Portrait~ipad.png to prevent the 6 plus from picking those up because those override the 3x image.

The following steps worked for me:

1. Add the images to the project (root directory or Resources folder) with the following nomination (I will describe them into the Portrait launchimages): Default.png (3.5 inch), [email protected] (4 inch), [email protected] (iPhone 6), [email protected] (iPhone 6plus).
2. Go to the target settings, App Icons And Launch Images on the General tab -> Set the Launch Image Source to not use asset catalog ('Do not use asset catalogs').
3. Remove the LaunchImage asset from your main image asset
4. Go to the target settings, App Icons And Launch Images on the General tab -> Set the Launch Image Source to use asset catalog
5. The XCode 6 is going to ask you about image asset migration from the existing images. Just click to 'Migrate'.

And it worked for me for each kind of devices on iOS7, iOS8. Note: If you check the new LaunchImage asset, then you can see it is really strange. It seems to contain only a few image without the images with iPhone6 or iPhone 6plus resolution.