I just completed a firmware up grade onmy Phantom 2. As soon a I powered it back on I got a warning (Abnormal Compass Data)

In the phantom 2 assistent software I get all 0s for the compass components... as if the compass is not connected, but It is!

Any ideas on how to fix this?

Edit: I just completed a firmware reset. still no joy.

UPDATE.
So after no solutions suggested here and I was unable to find any solutions anywhere online, including DJI support I figured I would have to replace my compass to at least test to see if the compass was the problem.

I figured it I was going to replace it I have nothing to loose in cracking it open... I figured I could at least test the wires. when I opened the little plastic box the circuit board with the magnetometers on it fell out! It was unplugged! I plugged it back in and secured it with some electrical tape. fired up the Phantom and it seems to be working!

I wonder how many people have bought new compasses because the board has come unplugged inside the compass??!!

There are other users that report hardware problems like the gimbal, GPS, and other components comming unplugged or loose. That's the nature of the beast with this type of product as it sub stains quite a bit of vibration and movement. As part of my monthly maintenance I check my plugs and wiring. Some  I have wedged (GPS) and some I have put a touch of glue from. A glue gun to secure. There  are things that  are needed to be checked regularly. Such as the motors. Check them for cleanliness I.e. Sand is a killer. See if the bearings are still good an tight and not binding. Right after flights check the, for overheating or getting to hot. They get a lot of wear and tear and need to be watched. Brushless motors will last a long time but the bearings can fail.  After a wile any cold solder joints will break loose so inspection for that can save your quad too. Check compass plugs and the plugs on the Naza controller as well as the small plug on the ESC motor controller. One of those comes loose and she'll drop like a rock. I guess you get the idea by now. Regular checks .. Look see's and make sure all plugs are tight will pay dividends.

Thanks roy, I do perform regular checks and I have actually re-soldered all my ESC wires and taped them down. My compass is the version 2, "anti-static" compass. it is easy to check the plug on the main board, but the plug at the other end is inside the housing that is part of the landing gear. I had to hack it open with a exacto knife! It is taped for now, but I will probably be gluing it soon... just to be sure!