I installed the GY240 gyro and the Electrifly 12amp ESC in accordance with Heli-max installation instructions, exactly. The helicopter flies perfectly. No problems at all. Check all of the wiring connections, especially to the receiver. I don't see how a new E-board could be effecting it.

You are using Lipo's correct. Upon plugging the battery in, I get a series of beeps. I then go full right rudder, another series of beeps, then full left rudder, a few more beeps. If then I go right rudder again, the tail rotor spins. I have been flying with this now for over a month at least once a day.