Upon powering up my P4 today, I received a message in the Go App that an update was available. As instructed, I connected my phone to the aircraft and it proceeded to update and ended with an "update successful" message. I powered everything off and now when I power up I get an RC Signal Lost message flashing in red on the top of the Go App. Can't start the P4 motors - won't function, obviously from lack of communication. I've tried Linking RC from the app but it times out. Tells me to press the link button on the P4 and after pressing in the button with a paper clip, I do get a remote successful but I still get the red RC communication error at the top of the app. A couple of other items I noticed are that the yellow led (tiny) on the card panel on the P4 is flashing two short flashes and upon powering up the P4, I get a message do not move aircraft, IMU calibrating. Very frustrating, not sure why, spent 4 hours trying to resolve.  Any advice would be most appreciated. My app version is 2.7.1, Aircraft Version is 01.01.0301, and RC Version is 1.5.80

There was another post addressing this issue (http://forum.dji.com/thread-48150-1-1.html), and one of the commenters indicated that he was able to resolve it by updating the GoApp version as well (from 2.7.1 > 2.7.2... Android) and then, afterwards, restarting everything again.  Maybe that will smooth things out.

The RC is not up to date. The latest is 1.6.0

DJI-Ken Posted at 2016-4-7 15:39
The RC is not up to date. The latest is 1.6.0

For some reason the P4 got updated but not the RC.  I deleted the Go App and reinstalled it and when I restarted, it downloaded the 1.6.0 update to the RC and it corrected that problem.  Now I'm missing the icon for the auto launch, even when I get a green ready to go indicator.  Also when I power up, I get a red warning indicator not to move unit, IMU is warming up.  Seems to take much longer to do that now.  Any thoughts, getting closer?

ptortora@mac.co Posted at 2016-4-8 05:07
For some reason the P4 got updated but not the RC.  I deleted the Go App and reinstalled it and wh ...

Post a screenshot, I've never seen the auto takeoff icon not there.
And to get the IMU warming up to only take seconds, you need to do a cold IMU calibration.
Put it somewhere cold for 15 minutes or so without the battery. before you install the battery and power it on, have the app and RC on and in the IMU calibration page.
Install the battery and power it on (perfectly flat surface) and hurry and start the IMU calibration as soon as it's linked up and the app lets you press the button.