In article ,
Fred McKenzie wrote:

I recently updated the FT-991 firmware to the July 24, 2015, version.
The update fixed some minor problems, but did not affect AM operation as
far as I can tell.

A new update to the FT-991 "Main" firmware was posted on August 17. The
only obvious improvement was the addition of another GPS option. I can
not tell any difference in AM operation.

One thing I did notice, was an occasional event where the radio stops
responding to its controls. One way to correct it is to cycle power.
Another is to keep trying different controls until you find one that
does something. Afterward, the others seem to start working again. I
suspect the problem may be time related, and it would start working
again if I just waited a minute or two!

Fred
K4DII