Help - APM 2.5 won't RC calibrate?

[Figwig]

Hi, I just got my second APM 2.5 board, after the first for my bat bone, for a 500 size quad. I've been having all sorts of problems, but the one that has really got me is that for some reason it won't arm, it claims that I haven't done the RC calibration, even though I have many times. I will literally calibrate it successfully, then go to the main menu and it claims it hasn't been calibrated! Never heard of this problem before. Any ideas?
This is my first forum post, so just gonna say thanks to the guys and flite test for doing all they do, and thanks in advance to anyone who can help!

 

[makattack]

Welcome to the flitetest forums! Have you tried swapping in your first APM board to see if that does the same? Have you looked on either the diydrones or ardupilot.com forums with the same problem? I've had some recent problems with my APM relating to flashing new firmware for arduplane, but was able to resolve it by reflashing, and resetting configuration values to default.

 

[Figwig]

I have tried swapping the boardss, which didnt work,but I haven't reflashed it yet, thanks for the help

 

[Figwig]

And there was nothing on diydrones or ardupilot forums :/