I just upgraded my LCD from 1002.1 firmware it had on it to a 1005.1 & 1006.1 according to the instructions on Samsung's official website. Upgrade went ok.
Now afterwards (no other changes in the setup), the white balance / color is messed up completely. Bright whites come out as pink. Tried a number of suggested Color settings from AVS forum, but doesn't help. I read that this is rather common and that the firmware upgrade can do this as it wipes out factory calibration settings. From what I hear, there's no way to downgrade the firmware.
TV's out of warranty at this point and I've very disappointed that an firmware upgrade from Samsung's official website would mess up my set. So far after calling their support, all I got was 'hold reset for 30 seconds' which of course didn't help.