I got my 10.1 WiFi about a month ago, and can't figure out why this is happening, and if it is happening to anyone else. Every ICS rom I install makes the screen flicker during boot, and it will continue to flicker until I turn off the screen, and then back on. After that there are no problems at all. I had the same issue when I install CWM recovery. I had to try 3-4 different ones, before I found one that didn't flicker.
It seems to me, that it might be kernel related, but I am not sure.
Any input is welcome.