This is a workaround for issue with the white screen:

I am using splash screen cordova plugin61.

In config.xml file I have set:

preference name="SplashScreenDelay" value="20000"
preference name="SplashShowOnlyFirstTime" value="false" 
preference name="AutoHideSplashScreen" value="false"
In platform.ready() I have:

import { Splashscreen } from 'ionic-native';
// ...
    setTimeout(() => {
        Splashscreen.hide();
    }, 1000);
// ...
This just shows the splash screen until you hide it in platform.ready().

Hope it helps somebody.