Two days ago I did my first flight after upgrading to FW V01.03.00.00 and all went fine.
On my second flight after changing the battery when I tried to start the motors I got an error message "Gyroscope's bias value is too large. Please restart the aircraft. Contact DJI Support if error persists.". I power cycled the Inspire and it all seemed ok and flew. On the third flight I got the error message again and it did persist to was unable to fly.

I reverted the FW back to V01.02.01.06 and was able to power up the Inspire fine and start the motors.  I have reverted back to V01.03.00.00 and so far it seems ok.  I did check the IMU and it said it did not need a recalibration, but I have done it anyway.

This is the first issue I have had with the Inspire in 6 months and it is somewhat worrying that this should occur.  The question is what has cuased this error message?

What if that promt to do a restart actually prevented a fly away?

Dji may have entered more ways for the bird to do self diagnostics and detect if any thing is wrong ... (just a thought).

It is a firmware upgrade error. How did you revert FW back to V01.02.01.06?

I got the same error about 10 min after I did the updates "Gyroscope's bias value is too large". Ive had this bird for about 6 months with no problems at all till now.

I have had that warning with previous updates until recalibration fixed it.  In fact it would not let me take off without recalibrating. If it is not a bug in this latest firmware then maybe it's a programming response to the notion that IMU degradation is causing some people problems?  Many people think frequent recalibration has prevented problems. I have not had any squirrely action with mine since starting to do it on average probably every 10 flights.  Doing it post update and post transport seems reasonable... it just always felt a bit risky to rely on that value interface as a prerequisite to calibration.