It's funny you should ask! I had a similar problem. One of my Lilliput 8" monitors did the same thing a few months ago and was sitting in mothballs as I was too busy to deal with it. I did some major digging without any luck and then finally contacted a US Lilliput representative for technical assistance. I just got an answer last week.
To flip it back over, turn on the monitor then press and hold the ">" key for about 5 seconds or so. It should flip upright again.
Originally Posted by Towball