*UPDATE* What's the firmware do?
I received some info about firmware 1.2.0. It is a legitimate version.
– Fixes issues related to poor quality third party batteries.
– Added code for upcoming remotes, accessories and lenses.
The source is a good one.
5D Mark II Issue (Direct Quote)
Also, 5DII twitch (confirmed as a metering spike) is known – keeps things looking even for the sensor which fluctuates charge/discharge based upon several criteria. It's working properly when it does this, sensing changes that are electronic and compensating for image continuity. It allows for smooth transitions, both while focusing and for proper exposure. The sudden opening and closing “bridges” the gap during a discharge. It is inherently random.
A post on POTN shows a 7D with what appears to be firmware version 1.2.0. The current official version from Canon is version 1.1.0.
See the thread for more: http://photography-on-the.net/
No word yet on what fixes or features were addressed. It's after April 1, so I think we can assume it's not a PS job.