I've got the fast flashing yellow lights after P2 boots up. Light on rec board is red, flashes red when pressed, and returns to red with no link to tx. I just had a horrible crash from approx. 100-150' and landed on asphalt upside down. Trying to trouble shoot what will get it back to flying. When hooked up to P2 assistant sw the imu had good numbers and ran the advanced calibration anyway. It responds to movements of the P2, however the compass values are blank and error message comes up saying connection needs checking. The crash pushed the compass connector on the main board over far enough when I straitened it out it broke off the board. I could see three of the five traces leading to the connector and soldered the compass wires directly to the board. Trying to determine where I can attach the other two wires, doesn't look possible so far. Modern circuit boards and components are far less repairable than those in the past. Anyway, all values for the tx are showing no connection. Have calibrated tx with rc sw but just can't get tx to link with P2. I'm trying to figure out if worth the effort and cost to fix, so far it needs new main board, that should bring the compass back to life, but want to see if my link problem is faulty rc board or I just haven't hit the right combination of steps to get link back.
Motors and esc units appear ok, gps antenna is cracked and replacements are available, but gps may be shot also. A lot to overcome, but its fun working on it and a learning experience. A new P2 is plan C.
Update: Been so busy with this troubleshooting I forgot to take in consideration that the crash happened due to two possibilities. What happened was at altitude the motors just quit and fell. I thought this was major component failure or I wondered if I had caused motors to quit with some combination of stick movements (which I doubt but can't know for sure). Both sticks may have been straight down for a second, but never more than that, and besides that's not a csc movement. In GPS and Naza mode.