Hello, my name is ***** ***** welcome to Just Answer.
I'm happy to let you know that I did some digging around about general repairs history on the Canon D4s through a friend of mine that works at a Electronic Facility Repair Center and he states that although he has seen the problem before, this issue is not very common among D4s at all.
Hope once your D4s is repaired through Canon, you don't get see any other issues with it....Thank you.
Sorry... I meant Nikon. The information I provided was actually for the Nikon D4. Sorry... I was just chatting about a Canon camera. It is correct that it must go to the manufacturer, since the retailer won't take it back after their return period - usually 30 days or less.
However, if you fill out the registration card that came with your camera (do this before service) it will extend your warranty with Nikon to 5 years.
I don't recommend doing anything to it yourself, since the warranty is excellent - 5 years is the best of any manufacturer. Not being able to insert flash cards into the slot if it is turned the right way is extremely uncommon.