So, I've had my T2i for about 6 months. I ran it with the latest canon firmware for 2 months, and then tried out ML. I went on a rap video shoot and it started acting wonky (menus not responding). I didn't have access to the internet at the time, so I asked a friend whom told me to just "delete ML from the card" yeah... wrong.
The camera would not power on after that. I took out the battery and card, and tried formatting it in my zoom h4n, which actually worked.. the camer booted back up and we finished the shoot.
I didn't use it for a month or so, other than to take a few photos and do some home videoes, and then i used it again for a vacation.. all was well. Then i didn't use it again for a few weeks, the next time i tried to use it. It once again wouldn't power on. i took the card and battery out.. left them out overnight.. still no go.
I put the card in my card reader and noticed there was some H4N files still on it, so I formatted it in the pc.. put it back in the camera, and it powered on.. everything was fine..
A week passes, and I use it to shoot some test footage.. everything is fine. I took it out for another shoot a few weeks ago, and again.. no power. So, I go home and try to attach it to the pc wth usb cable.. powered right up.. so at that point I reinstalled the 1,0.9 firmware and all was good.. until the next time i tried to shoot with it..
It was on for about 3 minutes, and the screen flickered and the power went off.. and it has been dead since.
I've been perusing forums and trying everything I can think of, and nothing has worked permanently.. different batteries, different cards, checked all doors, etc.
I've got the warranty return info ready, but I fear ML will still have a trace left on the camera which will mess up me getting anything done without a high price tag.. I was hoping I could figure out whats wrong with it so I didn't have to go that route. My camera worked flawlessly up until I installed ML.. I'm not blaming ML its just the only that I know of thats changed between the time it was working and now.