It appears that if I select a MCU = ATmega328PB and click detect, it properly reads the ID as a 328PB, no complaints, but it overwrites the form's MCU to be ATmega328P which of course fails subsequent attempts to read, write etc.
I can't reproduce this. I don't have a 328PB to test properly, however faking the returned signature to that of the PB will make it select the correct 328PB part for me.
It appears that if I select a MCU = ATmega328PB and click detect, it properly reads the ID as a 328PB, no complaints, but it overwrites the form's MCU to be ATmega328P which of course fails subsequent attempts to read, write etc.
Owen