That's very strange - I've never even heard of that happening before. If it doesn't happen again, would write it off as a flitch and wouldn't worry about it.

Removed the charger from a Samsung SGH-T819 and instead of showing the time/date and background image it had a completely white screen. Pressed and held the red off button and the phone shut off. Pressed and held the red button again and the phone went thru the initialization process except that EVERYTHING, ALL LETTERS and NUMBERS were reversed, not just in the reverse order but all characters were actually backwards like the backward R in the Toys R Us logo. Looked like I had just landed in Bizarro World. Turned it off and on again with same results. Did not try making a call so I don't know if it would try dialing the numbers in reverse. Removed battery for about 5 minutes and reinstalled it. This time it initialized correctly with everything showing up correctly.

Has anyone else ever had this happen Since it is not April Fools Day I am at a loss to explain what was going on. I considered doing a system reset but don't want to loose all settings unless I have to.
What happened in the EPROM to cause all data displayed to be reversed?