Maybe there is no problem, other than that people are drawing erroneous conclusions about cause and effect. The issue that some are posting about may in fact have nothing to do with failed firmware upgrade, or the firmware itself causing the problem, and everything to do with not doing an IMU calibration after that update. We don't know yet, but let me offer some general observations:
Consider the fact that the package your Inspire came in has survived truck and airplane rides and sometimes ridden halfway around the word to get to you. Its not unreasonable to assume that the package has received several shocks or impacts along the way. The IMU that tells the FC what level flight is could have been affected by those impacts, and it's always a good idea when launching
any new craft to do three things: update firmware, calibrate IMU, and do a compass calibration at the field/location you are launching from, then do a compass cal every time you
change location.
Any one who has questions about how and why to do that IMU calibration, head on over to the Inspire Owner's thread on RCGroups.com, where this issue has been discussed in detail. Hope this has helpfully added to the conversation.
Edit: Actually,
this thread on this forum has some good info.