Well I have been having problems with my FC40 after doing a firmware upgrade. After doing the upgrade I get a error 27 in Nazam and when I try to fly all I get is a constant flashing yellow light. The controller is nonresponsive as well. I have tried doing an advanced calibration as outlined here. [youtube]https://www.youtube.com/watch?v=Rx0YHQeWaj8[/youtube]. I have tried doing the paring of the receiver as in the advance manual. I did upgrade the receiver firmware in the process. Where can I go from here? It's new, so if I cant figure it out it may be going to back to Amazon if I can't figure out the problem.