I had a problem with the firebase plugin on ionic 4 the app just didn’t compile and I had to upgrade cordova-android@7 to android@8.0.0 the app compiled, but for the start just brank, there is Ionic info.
Ionic:
Ionic CLI : 5.2.3 (C:\Users\USER\AppData\Roaming\npm\node_modules\ionic)
Ionic Framework : @ionic/angular 4.3.1
@angular-devkit/build-angular : 0.13.8
@angular-devkit/schematics : 7.3.8
@angular/cli : 7.3.9
@ionic/angular-toolkit : 1.5.1
Cordova:
Cordova CLI : 9.0.0 (cordova-lib@9.0.1)
Cordova Platforms : android 8.0.0
Cordova Plugins : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 4.0.1, (and 18 other plugins)
Utility:
cordova-res : 0.6.0
native-run : 0.2.8
System:
Android SDK Tools : 26.1.1 (C:\Users\USER\AppData\Local\Android\Sdk)
NodeJS : v10.16.0 (C:\Program Files\nodejs\node.exe)
npm : 6.9.0
OS : Windows 10