Ashhar Farhan VU2ESE has indicated that there is a bug in the v6 code that prevents easy band switching to the 17m (18 MHz) band.
This is in ubitx_ui.cpp in line 746. It should read “17”, instead it reads “18” in the code as shipped with the first v6 µBITx off the line. This makes the button for 17 meters (18 Mhz) unusable, you have to use fast tune or direct frequency entry to get to 18 MHz.
Ashhar has patched the source code on https://github.com/afarhan/ubitxv6
He reminds those wanting to amend their code for uploading that the v6 source code compiles only when saved inside the sketches folder of the Arduino. This is an Arduino idiosyncrasy.