My X6100 is tied to a XPA125B amp using the ACC cable for auto band control. When using your firmware (which is great, thanks!) the XPA125B will constantly jump between bands while transmitting. The setup auto tunes fine with stock firmware. Is there a setting related to ACC in your firmware that I am missing? It's not that big of a deal, since I can easily use the XPA125B manual mode. Thanks again for the work you've done for the X6100 community.
Update: Don't think this had anything to do with R1CBU software. I stumbled on a message somewhere where somebody having a similar problem had placed separate power supplies on the X6100 and the XPA125B and it solved the problem. I did the same, and sure enough problem solved - I assume it was some sort of ground loop.?