After flying QX70 for 4 batteries it developed a problem:
When you connect a battery it spins only one motor for a second or two and stopped.
I cannot arm it after that.
Here what I did:
1. I reset the settings and it stopped doing it (spinning one motor).
2. Try to bind it and no success.
Another thing I noticed that I cannot spin the motors from cleanflight.
I also cannot upgrade the firmaware with a message cannot access bootloader or something. I know that there pins on the fc for boot I short them but nothing happens.
I think the fc is toasted.
Maybe somebody has a proposal what I should try next.