I have built custom App for my Moodle 3.4 site through phongap (Moodlehq phongap build ... GitHub) recently.
Everything works fine. Site URL takes automatically. But I replaced splash image and icon which has not been updated in app. Default Moodle splash and Icon are only shown.
What can be the issue. I didn't run gulp (being unknown of doing it), changed details in bundle.js as given in one of the discussion.