We have two small 3DR X8+ that have standard configuration (as sold). In both units we decided to incorporate the swift navigation piksi ver 2.3.1 gps and change the necessary parameters in the pixhawk board. Since we could not make the piksi gps work properly, we decided to take it away and return everything to the initial parameters (saved previously) and configuration (as bought).
In both units, the same problems showed up. And these are:
*The DJT fr sky rf module telemetry parameters were no longer shown on the 3DR FS-TH9X radio control only in the mission planner.
*The accelerometer and compass calibration was lost and even though we configured it again, from that moment on, every time we use either one of the drones we have to re-configure both parameters following the specified routine of calibration.
*We even calibrated the ESC of all motors thinking that there might be a problem with one of them.
*There was one time that really scared us, since it looked like the pixhawk lost the calibration when flying and the drone started behaving very weird, but afterwards it made to recover succesfully.

We have performed about 5 flights after this problem showed up and every time, before take off we have to go over the accelerometer and compass calibration routine in order to bypass the error message returned by the drone when trying to arm it. We even have to re-calibrate it if we turn off the drone, move several feet away from the initial position and try to take off from there.

Can anybody tell us what is going on?, what did the piksi setup changed that now we can no longer hold the right parameters to keep using them in every flight without recalibrating.
What can we do to reformat all parameters or wipe out completely whatever the piksi setup did to both pixhawk boards ?
Please help....thanks