Unfortunately, I also happened to ...
to save a few euros I lost several hours.
Even if it's an old discussion, it might still be of interest to someone.
I have partially solved it, disabling the internal serial monitor of b4r
and used CoolTerm (a free serial monitor)
to connect and view the log,
VERY IMPORTANT
to set initial DTR and RTS to off. (it would be great if these options were added to the serial monitor of future versions of B4R)
CoolTerm must be disconnected during programming.
Of course, I will no longer purchase this card model.
Greetings