Well guys, reading your problems and your solutions has been very instructive.
More or less same symptoms and same solutions, and when not able to get out of the white
screen,replacing the LCD/DIGITIZER assembly does the trick.My assumption is that in many cases when Resetting or factory Restoring doesn't solve the white screen problem,is because the connector that connects under the main board is not inserted completely,perhaps bent too sharp etc.etc. but anyway it is a faulty connection,therefore, replacing the LCD assembly solves the problem. Not necessarily because the previous Assembly was defective,but because this time around the male and female connectors were firmly mated.
I have a darn problem myself with my daughter's iPod touch 4th gen. I replaced the screen assembly last week,it went perfect,after 2-3 days it gave me a white screen.Tried hard reset,factory restore,nothing to do.The screen not glued to the frame yet.When resetting the iPod I had the Apple logo appear for 1-2 seconds and then back to white screen.I was ready to replace the LCD assembly when suddenly the word IPOD replaced the white screen,it was the lock screen background picture!
What happened was that without knowing, I was applying pressure on the top left side of the screen.I will let you know how I solve the issue.I have no time now.
Thanks for reading.