I am facing the same problem.
I am building the app with Phonegap and have followed the instructions in the document to the last t.
1. even after assigning correct site URL, the app continues to ask me the URL (does not go to my site directly)
2. Just as you described, I see my splash screen followed by a white screen and then the moodle splash screen. However, moodle splash screen does shoe my PNG file that I replaced for moodle_white.png.
Can anyone help?
Thanks in advance!